1997 Saturn SL2 A/C curious, yet annoying problem - HeLp!

[Shawnr001]

My A/C over several months went from cooling well, to only cooling for a few minutes after startup. At that time my pressures read 25psi low, 110psi high. I tried adding freon and removing freon... no change in cooling temp, or change to system pressures. The compressor had a ticking sound, so I replaced the compressor.

New compressor now. I started to add freon, pressure low jumped to 80-100psi on low side before even having 1lb of freon in the system, high side was 210-250, yet STILL no cooling. I revved the engine to 3,000rpm, high pressure went NUTS 400+psi, then compressor kicked off, I bled freon off, but high side STILL would get out of control over 2,500 rpm.

Suspect, expansion valve. Replaced expansion valve. Now low side 100psi, high 110-150psi, still NO COOLING. My opinion, low side too high, high side too low.

Back when my A/C was cooling properly would read 45-60 low, 160-190high.

My pressures are all over the place. What the crap am I missing? 2 bad expansion valves in a row? any thoughts, anyone run into weird pressure issues and no, or very little cooling? Is there a clogged inline filter somewhere that may be giving me issues? This car has an expansion valve, not an orifice tube. HelP!

[Cat Fuzz]

I think part of your problem is when you replaced the compressor you didn't evacuate the system. When you opened up the lines you let air in and that air needs to be removed. You need a specialized vacuum pump to do this. I don't say this often but I would recommend you let a shop do this for you.

[Shawnr001]

I did vac the system for 2hrs. got any other ideas?
8900b/MR2 Mozilla/4.0 (compatible; MSIE 6.0; Windows CE; IEMobile 7.11) UP.Link/6.3.1.20.06.3.1.20.06.3.1.20.0

[Cat Fuzz]

http://www.saturnfans.com/forums/forumdisplay.php?f=23


The only thing I can suggest is to go to the forum above and ask Fdryer. He knows more about a/c than I do.

[RC1488]

Originally Posted by Cat Fuzz

http://www.saturnfans.com/forums/forumdisplay.php?f=23


The only thing I can suggest is to go to the forum above and ask Fdryer. He knows more about a/c than I do.

+1. A/C is one area I avoid the most. I replaced the compressor in the '01, but got lucky in that it actually worked afterwards

[Shawnr001]

woo hoo! got it working!

Basically. Replacement compressor was bad, original one was good.
Expansion valve was bad.

Up past midnight last night determined to make it work anyway I could.
I put the old compressor back on since I knew that at least my old "ticking" compressor had a history of giving descent pressures.

With the new expansion valve and my old original 150k mile compressor the system runs cool and that old compressor doesn't tick and growl anymore!

What I learned: A sticking expansion valve can give very strange pressures leading to a noisy compressor when the compressor is fine!

[RC1488]

Glad to hear it