Paul Bell

iTrader: (9)

There's no section for A/C help so I hope this catches some answers.

For my 99 Trans Am, the A/C will not start blowing cold until I've allowed the engine to run up to at least 4,000 RPM. After that, it works just fine blowing cold air non stop. Turning the A/C or engine off and it happens again-no cold air until I rev up the engine.

I've checked everything obvious, nobody I've spoke to has ever heard of this.

HELP!

msydow

what are your high and low side pressures at idle? sounds like the compressor is not moving enough volume across the orifice tube. either by the clutch slipping, compressor worn, or low charge.

Paul Bell

iTrader: (9)

Wow, fast response, thanks.

I'll have to have the system checked to tell you the pressures at idle.

The compressor is about two years old, it didn't do this when it was first installed. I don't think any parts of it are worn, it's an AC Delco rebuilt unit. I also doubt the charge is low, when it works it's pretty good and cold.

I replaced the original compressor because (while over tightening a bolt) I cracked it's body.

Jeff Smith

iTrader: (44)

I had same issue with the bad compressor. when your motor run over 3,500 rpm and a/c start work blow. I replaced it and had freon filled up. no issue no more. I can't stand 90* heat driving daily bec. I woirks outside..

msydow

any updates??

UAE_Z28

iTrader: (14)

your compressor is going downhill, its running on borrowed time I think, that's my conclusion because you ruled out a low charge.

2000TransAmWS6

iTrader: (12)

"rebuilt unit" thats part of the problem... i work at an auto parts store, and reman compressors are generally junk.

like the first response said, the compressor is having efficiency issues. have a good AC shop check it out, and have them do the repair properly. AC work is easy to do wrong, and often problems don't show up until later. having someone do it properly will save you money in the long run!

firemech21

iTrader: (9)

I would agree that the compressor is crapping out.

msydow

i disagree about the a/c shop having to perform the work. you can easily do it yourself. once you buy a vacuum pump and a good set of gauges, you open a large door for yourself.

Paul Bell

iTrader: (9)

*sigh*

I'm starting to believe you guys, the compressor is junk.

I'm not gonna invest in A/C charging stuff when my buddies body shop has the full sized cart to suck the stuff out then re-charge it properly.

According to GM, the compressor number is 1137028 and listed at a zillion bucks. I did find it new from autopartstomorrow.com for $361.

Is this the way to go? Correct compressor or is there a "trick" compressor you guys might know about?

2000TransAmWS6

iTrader: (12)

i agree that you are opening a large door for yourself, i am a big proponent of doing things yourself if possible! but the main reason i suggest to have an a/c shop do the work is for the warranty. they will properly flush the system, will already have the proper tools to do it correctly, and will stand behind their work. with the parts being roughly $400 you don't want to have to do it again.

Paul, make sure you also replace the accumulator and orifice tube.

Paul Bell

iTrader: (9)

Thanks for the help everybody. As I still have A/C, the fix for this annoying problem will have to wait for funds. If it completely craps out, I'll have to postpone something else. If the car sits closed on a bright 90+ degree day, it gets brutally and unbearably hot inside.