A/C PSI readings for low and high side
Thread Starter
Launching!
Joined: Aug 2003
Posts: 215
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From: Central Florida
A/C PSI readings for low and high side I got my car back last summer after getting my engine replaced. However I didn't figure out my A/C was blowing outside temp air until this spring (car was down most of the time for upgrades). I got one of those Walmart kits with the guage and found the freon was low, however it was holding a charge. Now I only put in one small can of R-134a and the car is blowing cool now, but not ice cold like it did before. I don't want to put anymore R134a into the system without verifying the PSI pressures are correct. I plan on getting some good gauges to check.
Can someone please tell me what the LOW and HIGH side PSI pressures should read when the car is running at idle? I don't want to take my car somewhere local and spend $100 for something I feel I can do myself, I just think the shop didn't fill it to specs correctly.
TIA
Can someone please tell me what the LOW and HIGH side PSI pressures should read when the car is running at idle? I don't want to take my car somewhere local and spend $100 for something I feel I can do myself, I just think the shop didn't fill it to specs correctly.
TIA
10 Second Club
Joined: Apr 2002
Posts: 1,755
Likes: 2
From: Cincinnati, Ohio
You want the low side around 25-30 when holding at 2000 rpm. If it gets towards 20 or cycles on/off too much, add more. The high side can vary pretty well depending on the ambient temp that day. Also held at 2000 it should probably go no higher than 325lbs. To do it right though it should be vacuumed and then add a measured charge + 2 oz. off oil. It may not feel as good as before because a vacuum wasn't put on it prior to the recharge.
You want to charge the highside to about 2.2X's the ambient air temp.
You need to put guages on the car to do it right.
Was the system opened up? If so, you need to pull a vacuum and charge into negative pressure. Y
You might also need to add a few ounces of PAG oil. I believe thats what GM uses. If you lost alot of the oil in the system, you will burn up the compressor from lack of lubrication.
check out aircondition.com for some help.
You need to put guages on the car to do it right.
Was the system opened up? If so, you need to pull a vacuum and charge into negative pressure. Y
You might also need to add a few ounces of PAG oil. I believe thats what GM uses. If you lost alot of the oil in the system, you will burn up the compressor from lack of lubrication.
check out aircondition.com for some help.
