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thom4782 · 06-18-2013, 05:56 PM

Warm air blowing out of the vents when the AC is on generally means you have lost refrigerant or the compressor is not compressing. The two could be related. The compressor could fail in such a way as to leak refrigerant.

If it were me, I'd take my car to an independent AC shop and ask them to diagnose the problem with their specialty tools. Otherwise, if you do decide to do it yourself, then...

Step 1: try to restore cooling. You can purchase a can of 134a refrigerant and fill the system. Be sure to use the guage and follow directions so you don't overfill it. If you do get cooling again, it's likely it will disappear in minutes, hours, days, weeks or months depending on how big the leak is. The problem you'll face is finding out where the leak occurs. Cooling will suggest that the compressor is at least compressing the refrigerant. It still may be leaking.

Step 2: find the leak. When you refill the system, use a can of refigerant that contains dye. When the refrigerant leaks out over time, you can use an UV flashlight to see where the leak comes from. My guess is you'll see dye around the compressor, but the system could be leaking in a lot of other places. The hardest place to detect a leak is in the evaporator, which is located in the AC/heating box under the dash. I look for dye in the drain hose to find a leak there.

Step 3: Replace broken parts. Easy enough to do. It just takes time.

Step 4: Post repairs. When you get around to filling the system with refrigerant for the last time after repairs, take the car to a professional AC shop. They will evacuate the system to remove moisture and air from the system. This is hard, if not impossible to do, without the right equipment.

PS: I would suggest that you don't refill the system with a bottle that contains "stop leak." This stuff only works on the low pressure side of the system and it may gum up the internals. And, if you take your car later on to an AC shop, they wont be happy when they evacuate your system.

PPS: The other challenge you'll face is making sure there is enough AC oil in the system. If you can find a refill bottle with 134a, dye and oil, you're home free.

Hope this helps.

06-18-2013, 05:56 PM	#16
thom4782 Registered User Join Date: Sep 2010 Location: Foster City CA Posts: 1,099	Warm air blowing out of the vents when the AC is on generally means you have lost refrigerant or the compressor is not compressing. The two could be related. The compressor could fail in such a way as to leak refrigerant. If it were me, I'd take my car to an independent AC shop and ask them to diagnose the problem with their specialty tools. Otherwise, if you do decide to do it yourself, then... Step 1: try to restore cooling. You can purchase a can of 134a refrigerant and fill the system. Be sure to use the guage and follow directions so you don't overfill it. If you do get cooling again, it's likely it will disappear in minutes, hours, days, weeks or months depending on how big the leak is. The problem you'll face is finding out where the leak occurs. Cooling will suggest that the compressor is at least compressing the refrigerant. It still may be leaking. Step 2: find the leak. When you refill the system, use a can of refigerant that contains dye. When the refrigerant leaks out over time, you can use an UV flashlight to see where the leak comes from. My guess is you'll see dye around the compressor, but the system could be leaking in a lot of other places. The hardest place to detect a leak is in the evaporator, which is located in the AC/heating box under the dash. I look for dye in the drain hose to find a leak there. Step 3: Replace broken parts. Easy enough to do. It just takes time. Step 4: Post repairs. When you get around to filling the system with refrigerant for the last time after repairs, take the car to a professional AC shop. They will evacuate the system to remove moisture and air from the system. This is hard, if not impossible to do, without the right equipment. PS: I would suggest that you don't refill the system with a bottle that contains "stop leak." This stuff only works on the low pressure side of the system and it may gum up the internals. And, if you take your car later on to an AC shop, they wont be happy when they evacuate your system. PPS: The other challenge you'll face is making sure there is enough AC oil in the system. If you can find a refill bottle with 134a, dye and oil, you're home free. Hope this helps. Last edited by thom4782; 06-18-2013 at 06:12 PM.