Odd A/C performance..
Thread Starter
Instructor
Joined: Sep 2002
Posts: 173
Likes: 0
From: Mustang Oklahoma
Odd A/C performance..
My AC started doing this near the tail end of summer last year, so it wasn't too big a deal, but here we are coming back into summer soon, and I'd like to figure this out sooner than later.
About half the time, the AC works perfectly, as it is supposed to. No troubles.
The other half, it will run cold like it is supposed to, and then randomly, it will start warming up. Sometimes, it will do this after the AC has been on for 5 minutes, sometimes, after it has been on for 20. What I've been doing is turning off the AC, then turning it right back on. Sometimes this works, sometimes not.
I thought maybe the system was low on freon, but considering that when it is running, I can get 50 degree air out of the vents, I'm not so sure that it's low.
Any suggestions on what might be causing this?
Thanks!
ETA: Working on a '94 LT1 M6 with the C60 AC
About half the time, the AC works perfectly, as it is supposed to. No troubles.
The other half, it will run cold like it is supposed to, and then randomly, it will start warming up. Sometimes, it will do this after the AC has been on for 5 minutes, sometimes, after it has been on for 20. What I've been doing is turning off the AC, then turning it right back on. Sometimes this works, sometimes not.
I thought maybe the system was low on freon, but considering that when it is running, I can get 50 degree air out of the vents, I'm not so sure that it's low.
Any suggestions on what might be causing this?
Thanks!
ETA: Working on a '94 LT1 M6 with the C60 AC
Instructor
Joined: Mar 2009
Posts: 126
Likes: 1
From: Newington CT
Three things I know of could be causing this.
1. Low A/C charge...easy to check and 50 degrees is way too warm, should at least be 43 degrees...134a is very difficult to get as cold as R-12.
2. Condenser fan not working properly or condenser is clogged with road debris.
3. Orifice tube is getting clogged from compressor debris...this is the most likely problem and very common too and you will need an A/C tech to recover the charge to change the orifice tube and then recharge the system.
Good luck and do let us know what you find out.
1. Low A/C charge...easy to check and 50 degrees is way too warm, should at least be 43 degrees...134a is very difficult to get as cold as R-12.
2. Condenser fan not working properly or condenser is clogged with road debris.
3. Orifice tube is getting clogged from compressor debris...this is the most likely problem and very common too and you will need an A/C tech to recover the charge to change the orifice tube and then recharge the system.
Good luck and do let us know what you find out.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Could be ice too (look for it on the big line exiting the Evaporator when the problem occurs) which would mean the low pressure switch is faulty - or it could be an intermittent connection at the low pressure switch (which seems to plague '94 & up GM's) which would cut power to the compressor. I'd make sure the harness to the switch is clean and secure, or just go ahead and replace the switch. Also, if you have a scanner, get the pressure sensor voltage which should average 2 volts or about 200 psi with a/c cranking and both fans running which will give you some idea as to charge.
