AC Issues - Suggestions needed ASAP

The air won't get cold in my daughter's 2000 Grand Prix. Here is what has been done so far: new relay switch, checked fuse, new low pressure switch, compressor has checked out good, has freon.

Also, washed vehicle the other evening and washed motor - after this ac worked for a short period of time. We have taken car to two mechanics and they have checked/fixed the above mentioned. Both have given up - can't find what problem is. Now what???

Number one failure mode of automotive a/c systems is lack of cooling due to loss of refrigerant due to a leak--- you say it has "freon" - how much?? You cannot tell by the pressures you know-- 4 ounces will have the same static pressure as 4 lbs in your car.. so I am willing to bet you have about 8 ounces in a 1.88 lb system-- so look for your leak-- compressor shaft seal and compressor belly o-rings are most common leak location.

You say you washed your car and the AC started to work for a short period of time?

Have a look at your radiator and AC condenser. Make sure they are not covered in dirt. If the condenser is covered, no air will be allowed past it, and the heat exchange cannot happen. Thus causing warm air.

Both mechanics assure us that there is not a leak (thus their frustration). I don't know how they checked it but they both say there is plenty of freon and it isn't losing any.


The radiator and condenser have been checked - say it is okay - not dirt covered.


(Took to mechanics after washed motor and air quit again.)

analog or digital hvac controll?

As Tim asked, digital climate control or manual HVAC? Also, when you command AC on, does the compressor clutch engage? Have they measured both high and low side pressures and if so are the readings within specs for the then current ambient temp and humidity?

manual HVAC

Compressor clutch does not engage


both checked high and low side pressure - readings were within normal limits for current temp/hum

How can the readings be within the normal limits if the compressor doesnt engage?

3100 or 3800?

I know nothing about cars - just giving the information that I got from the two mechanics I've taken car to.

How do I tell if it is a 3100 or 3800?


I guess I am going to have to take it in to a dealer - the two mechanics we took it too came highly recommended from several individuals.

I know nothing about cars - just giving the information that I got from the two mechanics I've taken car to.

How do I tell if it is a 3100 or 3800?


I guess I am going to have to take it in to a dealer - the two mechanics we took it too came highly recommended from several individuals.

Uh Oh! :lol2:

I'm referring to the motor size. If its a 3.1 or 3.8, becuase I think the 3.1 has a different compressor that actually cycles on and off whereas the 3.8 I believe has the GM V5 type compressor and it constantly is running when the motor is.

It is a 3100 (if the big numbers on top of the motor are correct!) :)

We appreciate the help.

They all have V-5 compressors 1996 and beyond-- HD-6 compressors came off 3800's in 1996-- never to come back..

Thanks for clarifying!

If the compressor isn't kicking on the pressures cannot be within spec, so I would strongly suggest you take your car somewhere else. Strongly recommended or not, these mechanics don't know what they're doing as far as A/C work goes anyway. Maybe they have other talents, but obviously A/C work isn't one of them.

Thats a nice way of putting it Rich!

Okay - here is some vital inforamtion that was left out of earlier posts! Went back and did some more questioning....

Everything works great - cold air and etc - when hard wire to the compressor (thus the pressure and etc being correct) and the compressor clutch kicks in and everything....

But can't figure out what is causing it not to work when hooked up the correct way --- they have changed out relay switch, new low pressure switch... but don't know what else they can do

We do have it scheduled to take to the local deal on Monday

not hard wire to the compressor- meant direct wire (told you I dont know anything about cars!)