Yet Another n00b A/C Thread.....
 

Been lurking for a while...this is my first post :)

The A/C in my 87 944S (yes, wolfpri - another n00b taken in by that evil, baby-killing, crumb-stealing abomination unto God and Man that is the 944S) was just $erviced - and has absolutely no leaks. On cold startup it works fine but after running about 20 minutes the cooling gradually goes away completely. It seems like the compressor stops turning on. Once the engine is cold again, it's fine. The car has 44k miles on it. Any ideas?

is your heat stuck on? does it get real hot if the AC is not on? just a guess.

Welcome to the group.

Couple of questions:

1. Is it always cold when the engine is cold?
2. When the air starts warming up, if you turn the AC off for a while (10 - 15 mins) is the AC cold again?
3. If you don't turn the AC on until the car is warm, is the AC cold and then warms up?

Possible causes of this are (depending on your symptoms):

Stuck heater (heat will always beat out AC)
Sticking expansion valve
Extreme humidity

AFJuvat

Actually, this morning when I drove it it barely cooled at all - doesn't seem to be blowing heat, tho. It is extremely hot and humid here in Kansas - 95 - 100 deg. Can that totally kill the A/C? Also, what's the function of the expansion valve?

God, this thing's fun to drive. Just put in Koni yellows all the way around.:D

That really sounds like an expansion valve. If it were overcooling and freezing up the evaporator then at leat you would be getting A/C until it froze and shut itself down. But this truly sounds more like a bad expansion valve. Ignore what the service manual says about tearing down the dash board. You can get to the valve by removing the blower motor.

Threads were posted here 7/30/00 and 7/31/00 pertaining to expansion valve problem and instructions for replacing the expansion valve. I changed the expansiion valve in 2-hrs. Valve cost was $19.00 at auto zone. I converted to R-134a at that time and still cools to 42-48 degrees to date here in ATL. with 90 degree farenheit weather. (Subject: A/C woes can anyone help) The exp. valve is accessed by removing the windshield wiper arm and the plastic panel coverring the blower motor under the hood, and carefully peeling back the A/C line insulation covering the exp. valve/bulb and a/c line.

I have to agree with Scott. The fact that it didn't cool at all along with the other symptoms would seem to indicate an expansion valve. But just as general information that will hold for any A/C system: I had a customer with an '83 who traveled on business. He kept complaining that after 30 odd minutes of excellent cooling, the system would blow increasingly warmer, till he would just have to shut it off and open the windows. Five minutes later, he could turn the A/C back on and be good for another 20. We finally determined that he was modulating the temperature by using the blower. With the temp selector turned all the way to cold, and less warm air running through the evaporator, it would freeze. Running with the system off and windows open would let it thaw and work again. My point is to use the temp selector and fan to modulate the temperature.

have to say I like the Gromit Avatar LOL

Wallace and Gromit Rule

Matt

Here's another question since I'm having the same problem. Now that I've unwrapped the expansion valve from the black tar tape, what's the best way to remove it?