To fix an AC compressor clutch not engaging, connect a DIY AC recharge kit to the low-side port and squeeze the trigger to add refrigerant. If the compressor clutch doesn’t engage, follow the steps below:
1. Turn off the defrost setting, turn off the AC, start the engine.
2. If the center portion of the AC compressor clutch is not engaged, check for rust around the clutch plate, check the wiring to the clutch, and check the compressor clutch relay.
3. Do a visual inspection of the compressor, checking for rust around the clutch plate, check the wiring to the clutch, and check the compressor clutch relay.
4. Turn on the engine inspection and inspect low coolant content.
5. If the gauge does not hold/stay steady on 30, it may be due to a leak in the system or low system pressure.
6. Check the electrical system, including the fusebox, which is located under the hood near the driver’s side fender on 1999 through 2010 Silverado model years and on the left side of the instrument panel on older models.
7. If the compressor is not blowing cool air into the car, do a visual inspection of the AC compressor clutch and determine if you can see it.
8. If the AC is not blowing cool air into the car, unplug the low-pressure switch’s electrical connection and place a jump wire to jump the terminals connection.
9. Make sure the gauges used are pushing the shrader valve in to open the charge port.
📹 Can’t get refrigerant into your car’s A/C?Here’s how!
I show how to recharge your car’s A/C system using A/C Pro, EZ Chill, or similar DIY r134a cans. Here are some handy links: To …
Will low refrigerant cause the compressor to not engage?
When you turn on your car’s air conditioner, you’ll hear a click. This means the clutch is engaging. If there’s not enough Freon, the clutch won’t engage, so there’s no refrigerant for the compressor to pressurize. Your air conditioning system has no refrigerant! Another symptom of low Freon levels is visible leaking. If you see a leak, it’s probably Freon. It’ll look like a thin, greasy substance. Leaks often appear under the hood, inside the cabin, or under your vehicle. If you see leaking, take your car to a repair shop and have an ASE-certified technician fix it. An ASE-certified technician will check the system pressures with gauges and find any leaks. If a leak is found, the technician will fix it before refilling it with new refrigerant. If you’ve taken apart or changed your vehicle’s A/C components, technicians will ensure the system is free of moisture and air before charging it.
Do all AC compressors have a reset button?
How to reset an air conditioner without a button. Most air conditioners have a reset button on the compressor unit. It’s usually a red button that’s easy to see. To reset your air conditioner, just press the button. No heavy lifting required. If your air conditioner doesn’t have a reset button, follow these steps to reset it. First, turn off the power to the compressor unit. You can do this through the panel next to the unit. Turn off the power at the circuit breaker box.
Unplug the system from the power supply. This will turn off the air conditioning unit. Wait 30 minutes for the system to cool down before plugging it back in.
Where is the reset button on the AC compressor?
Where is the reset button on my air conditioner? If your AC unit has a reset button, press it to fix the problem. Look first on the outside of your machine, especially near the bottom near the ground. Your AC’s reset button is usually red and easy to find. If you don’t see a reset button outside, look inside the unit behind the service panel. Before you open the machine, turn off the power by flipping off the circuit breaker.
If you don’t have a reset button on your outdoor unit. If your AC unit doesn’t have a reset button, follow these steps to reset it manually:
Shut off the power to the condenser, which is usually next to the unit. Once you’ve done that, shut off the breaker in your circuit breaker box. Unplug the unit from the power supply board and disconnect the system. This ensures the AC unit is off. Wait 30 minutes, then plug it back in. Set your thermostat to “cool.” Then, turn the breaker and power supply back on.
How do you tell if AC compressor is bad or just the clutch?
The compressor clutch won’t engage. When you turn on the AC, the clutch on the compressor pulley should engage. The clutch is a plate on the front of the pulley. The AC off, the clutch doesn’t spin. When you turn on the AC, the clutch makes a click and starts spinning with the belt and pulley. If the clutch doesn’t engage or makes a screeching or whining sound when it does, the compressor needs servicing. Connected concerns. The AC compressor isn’t the only part that can go wrong. Problems with the AC system that are related to the AC compressor include:
Refrigerant loss: The AC doesn’t work because there’s no refrigerant. This is usually due to worn seals between system parts, but can also happen from damage to an AC line or hose. If the refrigerant level is low, the passenger compartment will be less cold. If it gets too low, the low pressure switch will stop the compressor from working. Low refrigerant levels let moisture into the system, which kills the AC. If you don’t find and fix the leak, the system won’t work. Refrigerant blockage can happen if the AC line or hose is pinched or damaged. It can also be related to a defective expansion valve or clogged orifice tube. Worn or broken serpentine belt: If the serpentine belt that drives the compressor pulley is worn, glazed, or cracked, it could prevent the compressor from spinning. If the belt is broken, the compressor won’t work. If your serpentine belt breaks, so will the power steering and alternator. If your car, truck, or SUV has a separate drive belt for the AC compressor, only the AC will be affected. A faulty blower motor can cause a loss of AC cooling ability. If the fan doesn’t blow enough air across the evaporator, it won’t cool properly. A clogged cabin air filter will also cause problems. The cabin air filter cleans the air as it enters the passenger compartment. Many drivers don’t know about this maintenance item, so it gets filled with debris and limits airflow. A blown fuse could also cause the AC to stop working. But don’t be fooled. Changing a fuse might get the AC working again, but it might not be fixed.
How do I know if my AC compressor is bad or needs recharge?
If your car’s AC isn’t cooling well, it may need to be recharged. If your car AC is not working right, you might hear strange noises, smell something bad, or see leaks. Can I recharge my car’s AC myself, or should I get help? It’s usually best to get help from a professional, but there are DIY kits.
What would cause an AC compressor not to kick on?
If you’re handy, now is a good time to check your AC compressor or schedule AC repair. Have the unit examined for blown fuses, tripped circuit breakers, broken thermostats, or dirty air filters. Dirty or clogged filters stop AC compressors from working. Set your thermostat to a realistic temperature. Don’t set your thermostat at 65 when it’s 110 degrees outside. It’s not designed for that. Heat pumps don’t work well on very cold days. They move warm air from one place to another. When it’s below 30 degrees, these systems don’t work well. Top Reasons Your AC Compressor Stopped Working. Not all AC repair problems are expensive. Knowing what’s wrong with your AC compressor helps you decide how much it will cost to fix it and how to avoid similar problems in the future.
What causes an AC compressor clutch to not engage?
The compressor could be broken. If the compressor clutch doesn’t engage, there’s likely an electrical or mechanical problem with the compressor. If the AC isn’t blowing cool air, check the AC compressor clutch for problems. If the AC compressor can’t operate correctly, you’ll get warm air even if you’ve filled the AC system with refrigerant. You may also check the engine coolant and oil to rule out other issues, but the clutch is the most important part for the AC to work.
How to reset an AC compressor?
How to find the reset button on AC units. This button is usually small and red and on or near the unit. Look for the reset button. When you find it, press the button for about three seconds and watch the air conditioner. If the AC doesn’t start right away, press the button again for three seconds. Your AC should restart after three beeps. If you can’t find the reset button, check the manual or online. Why do I need to reset my air conditioner? The most common reason for an AC unit to need resetting is when the protection circuit breaker kicks in. This happens after a power outage to prevent fires and explosions. A reset can also fix an AC that’s only blowing warm air, even when the thermostat is set to “cool.” Your AC might be blowing warm air for a few reasons. One of them is a general thermostat error. Sometimes a hard reset fixes the problem.
Where is the reset button on an AC compressor?
Most ACs have a reset button for minor problems. Look in the manual or online for the reset button location. It’s a small red button usually near the unit. The button should have a clear “reset” label. Once you find the button, press it for about three seconds and check the AC. If the AC doesn’t start right away, press the button again for three seconds. Your AC should beep three times and reboot. If your AC won’t turn on or doesn’t have a reset button, reboot it via the isolation switch. An AC isolator disconnects the power supply in case of an electric current problem or when the unit malfunctions. It’s on the wall next to the unit or at the condenser. The isolation switch looks like a light switch.
Turn the knob to the off position and leave it for at least 30 minutes. This will reset the electric components in the AC. Even when the power is off, there could still be electric charges in the components.
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Where is the reset button on AC compressor?
Most ACs have a reset button for minor problems. Look in the manual or online for the reset button location. It’s a small red button usually near the unit. The button should have a clear “reset” label. Once you find the button, press it for about three seconds and check the AC. If the AC doesn’t start right away, press the button again for three seconds. Your AC should beep three times and reboot. If your AC won’t turn on or doesn’t have a reset button, reboot it via the isolation switch. An AC isolator disconnects the power supply in case of an electric current problem or when the unit malfunctions. It’s on the wall next to the unit or at the condenser. The isolation switch looks like a light switch.
Turn the knob to the off position and leave it for at least 30 minutes. This will reset the electric components in the AC. Even when the power is off, there could still be electric charges in the components.
How do you tell if AC compressor is bad or needs recharge?
If your car’s AC isn’t cooling well, it may need to be recharged. If your car AC is not working right, you might hear strange noises, smell something bad, or see leaks. Can I recharge my car’s AC myself, or should I get help? It’s usually best to get help from a professional, but there are DIY kits.
Why won’t my AC compressor kick on when charging?
Why won’t the A/C compressor engage? Compressors don’t engage for many reasons. These include low pressure, a poor ground, a bad clutch coil, an open wire to the clutch coil, or a blown fuse. A/C compressor clutches get power in different ways. One way is for the PCM to operate the relay (the PCM interprets the sensors). Two, the clutches activate through a relay that is powered by the low/high pressure switches. Start by checking the compressor clutch fuse. If the fuse is good, Disconnect the compressor clutch coil from the electrical connector. Move it away from moving parts before checking power and ground. Set the A/C to MAX while the engine is running. If you have a voltmeter, check the battery voltage.
Wiring varies by year, model, and make. Some car manufacturers use the ECM or PCM to trigger the relay control coil ground. The computer needs to get a good signal from the evaporator temperature sensor, high pressure switch, and low pressure switch.
📹 I can’t believe Mechanics don’t know How to Recharge AC system correctly!
The Number 1 cause of Car AC not working is such a easy fix. Some mistakes are so simple example performing the Recharge in …
Why when I searched the web this entire summer in 118° in blazing hot Arizona did every single mechanic shop always give sound advise on how to “fix” it yourself but not a single one ever gave this advise? The all wanted $250 for the inspection, $280 for new switches, $450 for a new compressor, $250 for new lines, $195 for new harness and $95 for labor. This seems much more up my ally. Thank you for the article. Saved me money and many me days of heat stroke
You were to the point and I love that. I just spent $433 for my air conditioner and it still does not work. Took it back now they say I need a compressor. I didn’t let them do it because I felt like they should’ve done it right The first time. Now they want another $500 to do the compressor. I’m highly disappointed. I wish I had seen your website earlier.
It worked!!! 🙏 I’ve been working on this for 3 days and discovered other nuisance issues with blend doors but couldn’t get it cold after finally getting the rear AC running in my 2003 Yukon XL(wire connector under the plastic to the left of emergency brake, if your getting none or intermittent power to the rear AC blower motor 👍🏼) but thanks to this article the next 7 days of 100* won’t be so bad! Thank you Sir 👨🏻🔧🚜
This is a Very Helpfull article, Thanks ! I would like to add some advice that I DID learn from a Certified AC Tech . #1 . ALWAYS wear Eye Prorection when adding Freon . Freon sprayed in you eyes can Blind You Permanently . #2 . Always turn the can upside down when adding so you are charging with the Liquid, not the freon gas .
THANKS BROTHER! I was fixing to jumper a wire from the battery to the leg of the relay that controls the clutch. Your plug bypass was simple and effective since the plug was 4″ from the freon port. We couldn’t understand why the 2001, S10, compressor would not cut on. Good ole YouTube will make you smart! (Low pressure sensor) Then I got enough Freon in, that it was starting and stopping, like in your article. It still wouldn’t accept any freon. With the paper clip in place, it took Freon until it wouldn’t take any more. A little over a can. Temp at the vent with a temp laser. 36 degree. Oh yea!!!
Just wanted to say. Thanks Man ! I just got another new to me black truck. And as soon as I hooked up the can it bounced into the red making me think it didn’t need any and I had another problem. Added some any way and it kicked in. After buying the truck it would have been a few months before I could have got the ac looked at. Thanks again!
Thank you so much I learned a lot from your article. I never knew that the clutch clicking on & off was keeping the refrigerant from going in. That’s going to save me a lot of money in the future. & I did liked & subscribed 🙂 but just a request. When you do a article like this one. You started by showing that the refrigerant/coolant, wasn’t going in. would you please continue the article & show the gauge actually working & filling in the system. When I watch tutorials like yours and makes me feel safer doing it. Thank you again 😊
Your article is informative and simple to follow. But I’m very confused now. I recently learned that the HI pressure switch is on the Low side of the system, and the LOW pressure switch on the Hi side. At first it threw me, but then made perfect sense. So while the LO switch is located as shown in the article, we should be talking about the High pressure AC lines. And they are the more narrow, vs. the Low pressure’s thicker lines. On our 1999 RAM 1500, the AC charge port is very close to the compressor, on the thicker LO lines. I’m really baffled over this.
Thanks for this. I was about to watch some articles about putting a can in my Dad’s truck, but ran into someone I know that works on just about anything with a motor. He emptied the can…I don’t know how much went in truck if any, because he didn’t use a gauge. When it wasn’t turning cooler he bled air from the side by the battery. The clutch is staying engaged and the air is hot now instead of warm. What do I need to do now? If the clutch stays engaged, do you think I could successfully put some in
Had the issue of the compressor not staying engaged, finally b4 recharging it quit coming on altogether. The pressure gauge on the a.c. refrigerant bottle says the pressure is too high, so I let off all the pressure manually, pressure is still too high & ive tried jumping it from the low side & from the fuse box/a.c. relay(30 & 87)……nothing…..does this mean my compressor is shot? Lol or am I just not doing somethin right? Confuzzled 🙃🤔
If your compressor cycles on and off like yours did at first will it also show on the cans gauge a little higher reading? Mine is doing what yours is doing and when I put my can on it that has a gauge it shows that it’s almost full but it’s really not that cool. If my compressor is doing what yours is doing could that give off a false reading about how much freon is really in the system? Thank you for your article. 👍
My 2000 Mercury Villager is doing that very thing too. Unfortunately I didn’t see your article and took my mini van to a friends house who use to be a mobile mechanic before he became an All-Day Whiskey n Coke “sipper”. He did not try to bypass that switch nor did he tip the refrigerant back n forth to fill it. He turned the van upside down and wasted 2 cans of refrigerant and clutch still cycles on n off and van Is still blowing hot air. I’m going to be taking van to a/c shop tomorrow afternoon and will see if that’s their diagnosis. If not, I will suggest they do what you suggested and see if system allows them to recharge my a/c Appreciate your help
I’ll try this if the gauge pointer on my new can of A/C Pro waves back and forth while the clutch cycles on/off. Tried using a bottle of Super Tech that came with a gauge yesterday where I watch the pointer fluctuate between 20 psi and 45 psi for 12 minutes with nothing entering the system (I weighed the bottle on my kitchen scale before using and weighed the same after being removed). I figured their cheesy valve assembly failed to break the seal so nothing could escape to enter the system. I figure the refrigerant should enter if the low pressure is 20 psi.
So I’m currently having this problem. I know the clutch is going on and off when trying to add refrigerant. My question is did the keep the paper clip in while the car was on and while you added more refrigerant to the car? Or did you ” jump ” and connected back to add the refrigerant. Thank you in advance. I think this article will help me.
Can I jump out the relay instead? It’s a whole lot easier for me that way. I did it earlier and managed to get 12oz of refrigerant in a 19oz. system but after I took the the jumper off, the compressor still couldn’t run by itself, so I couldn’t continue charging. Do you think that being 7oz low would cause the compressor to not engage? Thanks.
Yep. Im stumped. I’ve got an 05 TSX, and the ac got to the point it wouldn’t always blow cold air. I could turn it of and back on and it would work again. I went ahead and changed the pressure switch, as I was convinced it was bad, bit the clutch still won’t engage. It’s full of refrigerant. I suspect the desiccant bag is clogged, and I’m getting a bad reading. I’m gonna try to jump it, and see if I can’t get a better reading.
I have a Buick Century and it seems the compressor is running but nothing will go from the can. It shows 25 in the white area but the gauge will not move and the can is still full. In fact, before I hooked the can up, the tubing was coold. Now it’s not. Nothing but hot air coming from vents. Any ideas? I’m using the Walmart kit that costs $20. for 18 oz
I’m driving a 2015 Mitsubishi mirage… I’m assuming the make of the car doesn’t matter(?). One second the ac is cool inside, then the next, hot air is pushing through the vents. As you stated in the beginning, we went and got a freon canister and we went to the low valve to push it through. It almost seemed as if it was pushing the freon valve away. Is it ok to do this trick without disrupting anything to my car? Thank you! I really hope this tip of yours would save us money we desperately need right now. Just wanted to get your two cents 🙂
So my Compressor kept switching on and off with only warm air blowing I did this and the compressor stop switching on and off but still no cold air it was reading in the green I pressurize it down Low as I can get it then really wasn’t anything coming out but air I put two cans of Freon in it previously thinking it was just low could it have leaked out and I need to try to do that again
2009 sierra 5.3l; my compressor keeps turning on and off, but when I go to connect the charge can gauges it’s showing my low side as really high pressure – it dips to yellow when the compressor is on, but there’s no way it’s overfilled – hasn’t been charged in 14 yrs. When driving, AC works great and is nice and cold but as soon as I stop and idle in warm weather, the AC starts kicking off and on and blows warm humid air, and it’s nasty.
What I found out is when you have an old gauge and a new can which they have now adopted a valve in the can that will close when you take your gauge off. If you have the old gauge you cannot get anything to come out of the can because it’s not opening the can right unless you buy an adapter and I got an adapter at Walmart for less than three dollars and then there were refrigerant came out of the can without me jumping anything. I have never had to jump anything any time that I’ve done this
Hey ragazzi io posseggo una jeep Renegade diesel 2000 cm³ 16 valvles . Questa jeep Renegade ho comprato nuova nel 2014 . Dopo dieci anni ho problemi con il climatizzatore vorrei refill myself perché i meccanici chiedono 250 Euro, vivo in Europa Italia. Sapete dirmi per favore qualche article dove ricaricano il condizionatore proprio allo stesso modello di jeep Renegade che ho io? Vi ringrazio in anticipo per il possibile aiuto
Hi Farm Dad, if you see this, could you tell me if my a/c sounds clogged, it doesn’t even blow from vent, so when My ex used a/c pro for it, it seemed to do nothing. It almost sounds like it’s clogged but I drained the a/c drain and a friend said it may be climate control? I’m sorry to bother you but if you have time please help with ideas!
Don’t I need to purge the AC first and hook it up to the AC cables and do that, then this? (2016 Tacoma 1234yf) ac clutch would not engage unless we did that same wire, by pass tip, then the GREEN light cabin would stay on longer than just 3 seconds) the tire kingdom in town wants 400$ min to do this. Ugh
Unfortunately they make paperclips out of plastic these days like 98% of everything else. Great suggestion. I sold my last car because nobody could fix my ac but everybody had a fix that didnt work. My replacement car also has no ac imagine that? Compressor sound comes with an occasional tick tock sound but not always & sometimes even when the ac is turned off. I was told its the compressor so i spent $200 for a new one and here we go again. No ac & the same old tick tocking sound with ac on or off coming from the compressor, the brand new compressor. Due to a stud bolt being stuck on the old compressor a regular bolt was put in the new one and coolant leaked all over. So… 7 hours later i am worse off than when it didnt work the first time and closer to $1,000 spent than $0 spent had i tried not to fix it. If a paperclip is all it takes to fix i will scream. But i will be damned if i dont force that brilliant mechanic i hired to at least try it so i can watch him squirm. I’ll edit my post if it does because out of ALL the articles ive watched they all point to the compressor or the clutch or both & simply said i am tired of everybody having a fix that doesnt work & then giving up & me having to go to the dealer to pay what? $2,000 or $5,000 on a car barely worth either amount. No wonder Tesla is making a killing. And Ford is building an electric F150. It gives people hope of saving money on repairs. That has yet to be determined but with 8,000 fewer parts than a gas hog & an electric charge for pennies compared to price of gas measured in dollars it looks better to me every year.
ok i learned long ago that running your compressor when it’s low on freon is stupid you wil burn it out fast … no articles show this anywhere …. all the ones show hook up to low side with ac switch on high fan lowest cold …. they all worked mines failed because the adapter was cheap plstic didnt compress the pin enough and it just spewed out in the air the neddle never moved of course cause my system is empty result i lost $69.84 buying two cans i should have went to other walmarts n got the ac pro that has mesh steel cable and the hard brass or steel adapter YOU learn from experience as always so tomorrw after i make enough to buy the ac just take off 1 hour and scoot to closest walmart and get the ac pro large 18 oz can or 20 oz …btw my car is 2011 dodge caliber
This didn’t exactly work in my situation…kind of. I have a 2007 Ford F-150 4×4 and the relay is the the fuse box behind the driver’s side head light. There is a square block fuse that you pull out and use the wire in the lower right and upper left prong slots to give the direct power to the compressor. Thanks for the article, it gave me a direction to look in for my specific vehicle 👍
Is this legit? Did it not short circuit the entire AC system? I mean DC isn’t AC But crossing positive and negative never seems to have worked out for me in the past! 💥 🫨😱⚡🌩️🥵🔥💣💥🎆🎆🤯🤬🤬🤬🤬🤬 The emojis are me working on cars and my experiences crossing positive and negative. So I guess I’m going to go against my better judgment and try this bridge thing he speaks of. Lol!
Unfortunately, this still leaves you with a potential problem. How would you know if it was low on freon to begin with? You have to test the pressure to find out. And you don’t want to jump the low pressure switch for that long with nothing being drawn into the system. Otherwise, you risk overcharging.
For those that don’t know there’s a pressure differential needed to actually charge your AC system. If you are in the green do not try to go higher into the green because for one the system pressure will be higher than your can so it won’t want to take anymore and two you need to leave some space for gas expansion so don’t try and over charge it. If your AC isn’t cooling first check to see if your condenser fan is on because it is what pulls the hot air out of the car and allows for your refrigerant to cool off before going through your vents. So sometimes you don’t need refrigerant but it’s mechanical. I just wanted to throw that out there.
Good information. These parts store charge kits are ok for adding refrigerant if you suspect the system is just low. If you’re trying to diagnose a not cooling issue and the charge is good the little single hose kit is useless. You need a manifold gauge set so you can read the high and low sides running and some cases checking the pressure not running can give you helpful information. For instance looking at your pressure on both high and low after they equalize at ambient temperature gives you a good idea of the charge level. There are charts online that show what pressure you should have at what ambient temperature. Another example is timing how long it takes the high and low to equalize can help diagnose an expansion valve or orifice tube issue.
Another great tip that I have learned is to watch for the lines near the dryer to start sweating and getting good and cold. If you keep adding much freon past that the cooling will reverse and the vent temps get warmer and some freon will have to be removed. Another thing if adding freon only lasts a couple weeks or a month there is a leak that needs to be fixed. Try soaping all the AC lines with the car off as static pressure should be close to 110psi and enough to cause bubbling. Some very slow leaks require draining the system and pressuring with nitrogen at 200PSI to find them. A leaking seal in an AC compressor shaft can be very hard to find because it only leaks under high pressure with the car running and producing 250 to 350 psi on the high side. I had a compressor like that in my dump truck. It finally got to where charging the system wouldn’t last all day. And I had soaped and pressure tested the line over and over finding nothing. So by process of elimination I determined it to be the compressor. That did fix it. Its been blowing ice cubes ever since I replaced it. If you change any lines on the AC system you have to add a little of the correct Pag oil back into the system and vacuum it down to get any moisture out. I haven’t always replaced the dryer every time I empty out an AC system especially if I just put a new one on but it is recommended. A moisture saturated dryer can cause your AC to freeze at the orifice or expansion valve and quit cooling.
Automotive technician here… I’ve been doing a mobile service here in Houston. I have a small inverter generator, Yellow Jacket vacuum pump, a small recovery machine and recovery tank. I remove the freon, pull a vaccum for 30 minutes, and charge with virgin freon to factory specs. All for $90. The problem with AC PRO cans is that they contain alot of oil to push a small amount of freon into your system. That causes an over-oiling of the freon, that decreases the heat transfer and efficiency of the system. Which leads to a decreased performance of the ac. My camry blows 28 degrees in the morning. In the Texas heat, my customers thank me for getting them cold.
Hands down the BEST tutorial I’ve seen on how to charge the AC system. NIA (Nates Interactive Auto) is an EXCELLENT instructor (I wish that I had teachers/instructors like him back in the day)!!! I have LIKED & Subscribed to NIA website. Thank you for sharing your skills, tips and wisdom. Looking forward to viewing MORE of your YOUTUBE tutorials.
You shouldn’t be playing around with those cans with a generic low side gauge. Just go spend $50 at harbor freight tools and buy an actual manifold set with low and high side gauges. All you’re doing is introducing air into the system with that can since the hose wasn’t purged. Don’t take this guy’s advice folks, just do it the correct way, at the very least purge the hose on the can. I understand that not everyone has a vacuum pump and a recovery machine at their disposal, but come on man.
Before adding any refrigerant to your system maks sure your Schrader valves are tight there are 2 valves that can leak over time,high and low pressure valves you can get a little screw driver at any auto parts store that has a slotted end to tighten both valves and before you tighten them get a spray bottle and dish soap water and spray the valves to see if they are leaking with the engine and ac running
I took auto mechanics yrs ago, the AC class was lacking in info so I went over to home HVAC and took a class there, they really explained it well. Superheat and subcool measurements, 2000 rpms, fan blowing on the front to simulate actual driving conditions. 15 to 20 degree drop. Ambient temp, interior temp, all these things come into play.
Saw on another article a very easy way to check if the system even has freon, this DOES NOT CHECK PRESSURE LEVEL but does check if there is some in there, use a screw driver or tool to press the valve in on the low pressure port and see if it whistles or makes some noise like air or freon is coming out. Very much like a tire, press in on the valve and it’ll let some out. Very good tips on this article!! If you’re perusal this article and are not understanding the terminology, aren’t sure which line you’re to be adding the freon to, which lines you’re even going to be messing with, any level of doubt where you’re thinking you’re “lost” then it’s simple, DO NOT ATTEMPT IT. Just bite the bullet and take it to a shop. If you connect and the pressure is in the green like he said, DO NOT ADD MORE as freon isn’t the issue. That’s something else in the system and adding freon will not only NOT FIX your issue, it can add more problems and lead to a bigger bill when you inevitably do take it to a shop. Had a friend ruin his entire HVAC system because of doing that. I (and you should as well) know what type of freon to be using, which line is the low vs high pressure line (low is usually a thicker line and high pressure is usually a smaller line), know the HIGHLY suggested environment temperature to perform this in, make sure you’re outside or in a garage with proper ventilation, and definitely wear safety gear IE SAFTEY GLASSES AND GLOVES. If you’re injured, specially your eyes, you won’t be able to enjoy the reason you even did this repair in the first place, COLDER AC.
“I have gauges in the vents.” Thorough instrumentation is a Very Good Thing. There are things going on that our senses cannot detect–especially if we are not trained and experienced. Excellent article. I’ve done a few recharges, tried my best to follow the directions on the can and in the manual, and still learned a few good points–in the shade with all doors opened being two of the best. Thank you.
I just read three different brands of AC cans. (All of them were 134a of course since that is all that is available on the market) None of them said anything about doing it in the shade or leaving doors open. Logic says the door reference is because you don’t want your thermostat to turn off your AC in the middle of the procedure. I suppose the shade thing is about not letting the ambient temperature getting too hot since temp is a factor in the pressure shown on the gauge. Probably both good ideas to follow but definitely not universally recommended or required.
I will add you should also use a pressure gauge to monitor the High pressure side as well. If the High side stays too Low (e.g. below 100 psi) or goes super high (above 300 psi) while adding Freon then there is a blockage / malfunction in the system and you should stop immediately. Failure to do so risks damaging the AC Compressor or something else in the system.
This is a good way to charge your A/C. If you have at least 2 digital gauges that you can put in the dash vents, one in each side as far apart as possible. If the system is low then one side will usually be drastically different than the other side. There are a lot of pro mechanics commenting and there are many good ways to charge. The most accurate way I was taught at a Four Seasons A/C workshop is with a contact type thermometer system. With one attached to each side of the evaporator lines, as close to the actual core as possible, usually right at the firewall. Once everything is running, with the A/C on high and the car doors open, a condition called “Maximum Heat Load”, the temperatures should be the same on both sides of the evaporator +/- 3 degrees. If the outlet temp is higher than the inlet temp the system needs some freon, if the outlet is lower than the inlet the system is overcharged. The recommended charge amounts on the stickers are usually pretty close but due to manufacturing variances a couple ounces either way might be needed to get the best A/C cooling possible. Using the contact thermometer method you adjust in small increments until the desired inlet and outlet temps are achieved. Personally I still prefer the systems that use a site glass. They are far less common today. They were only used on expansion valve systems which were the norm 50 years ago. Fixed Orifice systems became popular in the 80’s but with less efficient systems today due to lower charge amounts the expansion valve is making a comeback.
Spot on a little instruction helps the young guys breaking into the business and the old guys who got passed over by the new tech. So many hater’s out there no wonder mechanics have the well deserved reputation as rip off con men. I’m 67 and have been a mechanic all my life, most people can not afford or find a legitimate shop anymore, the shop’s are just not out there. Most of you guys know this and most shops don’t have the latest diagnosis equipment and have resorted to just part changers till they get it. AC work has gone high tech and filled with regulations. More power to the car owners! Yes you can mess up your ac if you don’t read the instructions. No you can not blow up a can of Freon hooking it to the suction port.
Great tutorial on top off for a non-leaking system. I finally topped off my 2006 Tundra which NEVER was cold since I bought new, just kind of cool except for at night. Had the Recharge kit for over 10 years stashed in my truck supplies cabinet and just found it again after pulling out 5 qt jug of Mobil1 oil for a change and read up and followed all instructions precisely, noting ambient temp/humidity. That was about 3 months ago and it is still blowing MUCH Cooler! So glad I didn’t let Scottie K continue to scare me away from doing this and bow driving cool in the Hot Ass Florida Summer! Thanks for your thoroughness. I didn’t see the leaving doors open but it still worked great and now I know for next time.
I like your article, you’re absolutely right about everything you said and I agree.. not long ago there was somebody that wanted a can of r134a put in their system and I showed them that it didn’t need it because it was in the green but they insisted so I did so I went from 35 in the green down to 30 by putting some in there (I couldn’t figure that out) I gave them what they asked for even though it went against the directions.. some people just don’t get it
Hello Nate, I have a question. Unfortunatly I had not seen this article before doing this, and I might have messed this up. I just tried to fix my airco in my Kia Picanto 2012 with one of those simple kits with a can of refrigerant, and a hose with a gauge. (mine did not come with a temperature setting). My airco had just gradually become less cold over the years and now it had completely stopped working. I was hoping for a quick fix for now, but it didn’t work out so far. When I connected the kit with the gauge to the low pressure side, it showed no pressure at all. Then I filled it untill it showed 60 PSI, with the engine and airco on. (was aiming for 50 but gone a bit too far). After that I drove around the block and when I drove away, cold air was coming out of the vents, and I thought it was a succes! but.. this only lasted for a very short time, a minute or so. (that doesn’t sound too good, right) So now the airco still doesn’t get cold. Now, when I check the pressure on the low pressure side, the gauge shows 60 PSI, engine and airco on, or off, there is no difference. Also, the pipes don’t feel cold at all. Since it is also showing 60 PSI with the airco and engine off, I’m thinking… maybe there is still not enough pressure, because with the airco off, the pressure should rise far into the red zone… (like 100 PSI) if i’m right? Do you think it’s worth it to try and get another can of refrigerant, to build up the pressure and see if the airco will actually activate? (I can’t seem to spot any compressor pulley turning on and off when I turn on and off the airco, everything seems to be turning always, even with the AC button off.
If you have the system drained and have worked on it to repair the system, adding r134a which has some oil in the can, will that fill the system with the correct amount? some shops sell just r134, which I guess is fine to top up a system, adding extra oil, without knowing how much is in the system is not good?
I use manifold gauges on high & low side when charging. The gauges help pinpoint a problem, if there is one. Using a temperature/ pressure chart is an effective guide in dialing in the correct pressures for maximum cooling/ taking into account the ambient temperature. Remember to bleed off just a small amount of refrigerant from the hoses as you are connecting the lines, to avoid getting air into the system. And NEVER, EVER, charge through the high side! This could be fatal.
Up to 40 years ago buying a recharge kit (just a hose with valves and a clamp that came with instructions) and/or a case of R-12 refrigerant was something nearly everybody did – the stuff was available not only at the auto parts store but at places like K-Mart. When I was stationed in Texas I was recharging the AC for everybody in the barracks as long as they brought their own R-12 and a six pack of beer. Cheaper and easier than going to a garage to have it done. Then all the various new regulations and laws came about and suddenly you couldn’t get refrigerant in many places unless you had a license of some sort.
Question: 07 Civic EX. A/C wasn’t charged when I bought it. I was told it just needed freon. Bought a charge kit from Walmart. Put it on the low pressure side to change it. It was empty. Turned everything on high/max, pulled the trigger, clutch activated but the gauge shot to the red/full/danger zone within 3 secs. I know it’s not full. What do you think?
Most mechanic shops are required by the EPA to use the proper refrigerant handling systems that are capable of capturing and recycling refrigerant from a vehicle. That can does not meet those requirements. But it is perfectly legal for the do it yourselfer to use them. But if it is done in a shop, they have to follow those regulations, be certified and the equipment to do so had to be certified.
You shouldn’t use those cans, you always want to use a set of gauges, you can’t accurately charge your system without monitoring what the high side is doing as well. You need to see both low an high side pressures in order to accurately diagnose the problem on an ac system. These cans are marketed for taking money out of your pocket, an not resolving the underlying issue, which will eventually cost you more in the long run. Point is if you don’t know about AC systems an still want to go the DIY route. Go by yourself a set of gauges an do some research on the internet, an learn on your own. Or save your money take the vehicle to a reputable mechanic, not a shade tree dude with all the doors open an a can of chiller.
I’m under the impression no one should be messing with their refrigerant unless they know what they are doing. I’ve been in the refrigeration business for over a decade now and I’ve never once “topped off” a system. I’ve pulled gas in and out to account for ambient temp but not any other time unless a tech didn’t know his head from his ass. Low refrigerant always indicates leak if all other conditions are satisfactory.
5 years ago I was on an out of state road trip. A/c kept getting warmer and warmer. Auto shop said $1,200 to make it right. Didn’t have the bucks so I put in two cans of Freon,with the gauge and followed instructions on can. Held cold for a full year. I have added Freon each year for 5 years and the a/c continues to work. For $30 a year vs $1200 to fix I consider a win for the little guy.
HFC R134A must be charged by MSD specs (weight) The over the counter stuff is just for an emergency. There may be several reasons as to why your vehicle’s AC is no cooling properly. If the vents inside the car don’t feel cool and the system is set at max, then it’s either a leak or one or more of the system’s components are faulty. However, you could try the old rattle can charge to see if it will get cooler. If it does get cooler then wait to see for how long. If it goes back to warmer again, then more than likely your system is leaking. Note: Not all mechanic shops are truly AC specialist. If you really want the issue properly diagnosed and fixed, and if you’re willing to pay the $’s, you need a reputable AC service shop. Most mechanic shops will go through a process of elimination and never find the culprit. And of course, it all comes out of the car owner’s wallet. Just saying 😎
First and foremost your ac is a sealed system so you shouldn’t have to top off. This works if your in a pinch but remember if your low, there is a leak somewhere. A few things to remember. If the expansion valve or orifice tube is clogged or stuck you could keep adding refrigerant to the low side suction and it may only show up on the high side, so without a manifold gauge you could still be overcharging and not know it if you are using a low port pressure gauge only. Normally, after all the refrigerant is retrieved, and repairs made, I will vacuum for a few minutes then let it sit at -30hg for at least 30 minutes to make sure it is still holding the same vacuum. Then I’ll vacuum for at least another 30-45 min at get all the moisture out. With the vehicle running and ac on, I’ll purge the air in the center vacuum line until refrigerant comes out and then open the low side to let in said refrigerant which is measured by weight (not the low side pressure). Again, do you have to do this using a manifold and vacuum or an ac machine… not really, your just getting all the moisture out and extending the service life of the compressor and the rest of the ac system.
Charging a car/truck’s A/C is NOT rocket surgery. If you re-charge and it doesn’t blow cold air, lick the tip of the connector and say “feces” three times in row, and then throw garlic over your LEFT shoulder (NOT right). Then, start the motor and do a somersault. This is the PROPER way to recharge your system. You’ll need a snow bib in the summer while traveling in your vehicle. 👍Your Mom taught me that…
One tip I would add would be to have someone hold the throttle up just a little above idle, this helps the compressor take in the refrigerant, also a pan of hot water to put the can in, not necessarily when you start but shortly after you start to charge, because the pressure in the can will drop and the can will get really cold and the refrigerant will not go in as the pressure in the can is to low.. warming it up with the pan of HOT water will raise the pressure in the can so it will go into the system.
6:57 you did not purge the atmosphere from the fill hose. You have introduced air and moisture to this system. Line purge is considered deminimus release and allowed. Even small amounts of atmosphere can become the early failure point of ac systems in a few years time. Use air to blow out the low side port after you wipe it down, anything retained within that port gets pumped into the system. These are critical points.
There’s a TON of incorrect information in this article, and very little that is correct. Whole thing is a guess that the system is low on refrigerant; high side pressures can help a little with that, but only real way is to recover and weigh the refrigerant – like with real shop equipment. NEVER use any sealer or refrigerant containing sealer, and use a real set of gauges.
So I bought a can to charge my wife’s jetta TDI diesel sport wagon. I followed the instructions which are straight forward. When was finished charging a re move the hose and the coolant blew out the low pressure fitting. I think the pin got stuck in the down position leaving it open and allowing th gas to blow out. Any suggestions on how to check the fitting?
I put the refrigerant can in a container of hot water to provide heat for vaporization and it charges much faster. Also, if you have a full gauge set like I do, the can tap that I have will not work with the self sealing cans available everywhere because when the tap is withdrawn, the can seals itself. These cans are made to work with the type of gadget shown in the article that has a hollow tap that allows the refrigerant to flow.
Ok, but as you increase the engines rpm’s head pressure gore’s up and suction pressure goes down. I have 2 superheat thermometers like yours and neither of them work. I put new batteries in them but still don’t work. Do you know anything about this? It was a real nice set with a core removal tool so you can slide thermometer right into the refrigerant flow for superheated or subcooling!
I’ve done this! I recommend perusal temp at air vents very closely while adding refrigerant! As soon as temp starts falling STOP!!!! If you continue adding refrigerant (too much) you just lose the benefit you achieved!!! The system fails if you add too much! System is ultra sensitive – so just monitor those vent temperatures very very closely and wait a while between top up squirts while system stabilises. Do NOT overfill!!!
my 2015 grand caravan’s ac does not blow cold when I stopped (but ac and engine are on) for example it blows wonderfully when I drive. When I wait at the stop sign ac makes a noise like air is leaking and ac stops blowing cold air. After that when I push the gas AC is ice cold. Please advise. thank you
I also see where it says “STOPS LEAKS” on the can. That means it has stop leak in it which clogs the orifice tube and other components completely destroying your ac system. The only proper way to recharge a system is to reclaim the refrigerant, vacuum test the system, add oil if needed (depending on how much was removed from the reclaim), and refill to proper specification using a weighted machine. This freon in a can is snake oil.
I could add from my recent experience is that you connect the hose to the low pressure port while the engine is off, then you switch the car on to do the process, when all done you switch the car off to disconnect the hose .I.e connecting and disconnecting while engine off ( all of this was on the instructions guide on the gas cylinder I bought)
If your charging the LOW side of the system you need to make sure your adding refrigerant as a liquid and not a gas. That can should be turned upside down then allow refrigerant into the low side of the system. You only add refrigerant in a GAS form on the high side of the system. Maybe that’s why the hose is so short?
it looks easy but be careful. years ago I lived in a small apartment complex. the ppl on one side of me, very nice ppl, the husband worked less than a mile down the road at a Ford dealership. they worked on his a/c that day. he drove home said it worked great now. about 5 minutes after getting home I heard a loud explosion. something in his a/c system blew up. there was pieces of hose and metal on the ground under his car. BE CAREFUL.
i work for a auto parts dealer and i can tell you that every A/C machine has the freon tank with the valve at the bottom. ( upside down) you can do it either way but if it is ” upside down” the liquid freon is being transferred to the system as a liquid as opposed to being transferred as a gas. Both will work but but the upright way takes way longer and puts more work on the compressor . Be cool everyone.
So what does opening all the doors do for you? Would expect an open window to do the same if you are concerned about preventing the condenser from freezing up under the dash when doing “max ac” which usually forces recirculation anyway… also you charged to the the middle of the green, you said anywhere in the green was where you should stop. If refrigerant is too low you might have to jumper the compressor to force it on to pull the freon in.
@ 3:45 “You need to keep the can upright, in the 12 o’clock position, while using.” YOU didn’t though. The can was shown on its side while on top of the engine, in this article, while you recharged the system. No doubt because the can is too tall, the hose is too short, and it CAN’T be held straight up and down while it’s hooked up. This is the third article of yours that I’ve watched in a row now that has conflicting information in it. Get it right or don’t do it all, imo, because you confuse your viewers. If i can’t believe in what you’re telling me, then there’s no point in wasting my time perusal your article’s.
What’s the theory behind having the doors open when recharging? I used to just add refrigerant back in the days without gauges or anything like them. Definitely overcharged the heck out of them but never experienced any problems other than icing forming at some of the vents. Cold AC like the arctic so had to run on low or medium, never high or windows got fogged up. Coldest cars in the neighborhood were the ones I serviced. Not a mechanic but it was a hustle and the client list kept growing then came regulations. $80 back in the late 70’s was great money. I never opened the doors and worked great but it’s great to know the science behind it.
Do you still only charge to the green if you just vacuumed out the ac system and made sure ot wasn’t leaking? It says to put 20 Oz in my vehicle. I put a little over 9 and it’s in the green but not all the way. I’ve read the bottle atleast 15 thousand time and it says go by the ambient temperature, which I’m in florida, so 300 degrees f…kidding, but 85 95.
So JC is My BF and currently off The Reservation. Help! Heat index above 115* 2010 Vibe stops blowing cold. Tried to add r134 but compressor is not engaging. Fuses and relay seem ok. My budget is less than zero! Any tricks of the trade di tell, about ready to try that paper clip jumper to manual start! Its just so hot this summer!
certified mechanics. Do not use cans. They only use an a/c recycling machine that recovers Freon and installed the exact amount. Auto stores should not be allowed to sell Freon to anyone without a license and proper training. If you are caught evaluating Freon into the atmosphere, you can be fined up to $10,000.00 .If you overcharge a system and blow a high pressure line. You may become blind.
I have a 84 ford bronco 2 i live in utah so in the summer time there is little to no humidity and i replaced the orfice tube then i didn’t even evacuate the system and i charged it up and my ac blows out at 8 degrees and it works great and i have never had any issues of it locking up with ice in the system, 8 degrees is the coldest ive ever seen coming out on a hot day i just about could get frost bite but it sure feels good, my bronco has 333,000 miles on it and its still going i love old vehicles that were made to last, i think i did a great job on my ac but there is those people out there that have no clue to what they are doing
The R-134a container also needs to be turned upside down and charged on the high side to provide the correct mixture. R134a is a blend of refrigerants that separate in the vapor form which is why it needs to be charged in the liquid state. Charging in the vapor state doesn’t give you the pure mix as it was intended.
90% of those cans have sealer in them, as does the one he’s using in this vid, and 100% of shops will not work on that AC system if it has sealer in it. This is a big no no since if you have a leak and need to take it to a shop for diagnostic and repairs no one will work on it after putting that stuff in. The sealer in them will cause solenoids in pro machines to stick and need serviced which is expensive on a high end recycling machines. Take it from a 30+ year automotive tech do NOT use these, especially if they have sealer in them.
Basic A/C: evaporator does well around 40 degrees give or take. For r-134 thats 35# on the gauge. I like to run it just slightly under that abot 33#. If you have an OBD tool (just a cheap one), be sure to check engine load when you turn on A/C: the % will go up when both the clutch and compressor are in order. Odd points of note? A bad AFR sensor in the exhaust is capable of making it short cycle: if engine rpm’s go too low at idle, the computer will drop the compressor load to keep the engine running in many cars. A plain short cycle may be due to system charge, but without an ultra low idle.
A clean condenser coil is quite necessary for proper charging…an AC cannot cool if it cannot breath…always ensure that you have a clean cabin filter if equipped before charging…Always hook up the gage before starting the vehicle, if the system appears empty, you may have to pull a vacuum on the system before charging…this will also help you determine if there is a massive leak in the system…Once you start the AC, if it is showing high pressure, make sure the AC clutch is engaging…Also ensure that the coolant fan is running when the AC is on before charging the system as well as the blower.
Hi I don’t know your name I just come across your article and I like it I just want to ask you a question I a 2010 Mazda CX-7 no AC on it just want to know if it’s ok to charge it with a can or should I take it to a professional mechanic just a little concerned thank and have a good day buy the way my name is cornelio
I’ve been doing this since the R12 days with the old POAS TV valves now their all 0rifice tubes so there’s nothing controlling or adjusting the flow of refrigerant so as you’re charging the high pressure side will build until the electric fan cools it down. That to me is one of the most important things no one tells you to make sure the fan is working or starts working while charging the engine radiator fan/ acc condenser fan must operate properly
“You must perform this in the shade! It says so right on the can!” Proceeds to charge it in direct sunlight. Lmao just teasing. But just out of curiosity, why does it matter if you do it in the shade? Is it because the sunlight can heat up the can and mess with your pressure readings? Also why does it matter if the doors are all open? I can’t come up with a reason for that one. Thanks for the article!
If your system is low, that means that there’s a leak…not supposed to change system with known leak unless checking system for leak (a die maybe added to help find leak)once leak is verified/ fixed you must run vacuum for x amount of minutes holding a vacuum verifying fix is complete before you can recharge system returning vehicle back to customer. There is more to it depending upon the leak/repair needed.
HELP! After I had a new belt replaced in my 2000 Acura TL 3.2 by professionals, I noticed that now when I turn on my Air Conditioner (I.e. push the AC button) it will rattle or make a sort of buckling sound. I immediately turned off the Air Conditioner as fast as I could….all the while wondering WHAT is causing that? It did not do that “prior” to having the belt replaced. It’s the oddest thing ever because I didn’t have any problems with my AC (well, that is until now). 😞
Vehicle A/C is best charged by weight! Not pressure, but to do that you have to recover the refrigerant, and have scales etc. Pressure test the system for leaks with dry nitrogen, as if really low probably have a leak. First thing to check with the engine off & low noise level, is that when you 1st open the protective caps over the port they are not pressurised/make a fizzing noise when open, I get a lot of people with slow leaks and 99% of the time it’s the valve cores/Schrader valves leaking where the seals or springs have failed, or just that they never seated correctly after a top up.
Unfortunately every repair facility isn’t created equal. While some places know what to do some do not. I had my wife take my in-laws crv to a repair facility to have the system evacuated and charged because I didn’t want to do it, and I changed the condenser and compressor. I put it under a vacuum for about 45 minutes to check for leaks and then left it evacuating just because. She came back and told me the facility said it was empty so they charged it. So I asked what do you mean it was empty an evacuation isn’t a reclaiming. They never evacuated it even after I had her request it. Just because they have an ac machine doesn’t mean they know what they are doing.
E low side cap prevents debris from entering the system. Before consulting the fix a flat style of recharge (which is full of stop leak) I suggest using a set of gauges and do the job right. I don’t mean to come off as being rude, however I strongly suggest not pointing fingers at actual “mechanics/technicians.