Boyce

I read Wally's HVAC dissertation. Thanks Wally! My 134a AC (no rear air option) only cools at sustained, above-idle RPMs. My mechanic says the compressor is "weak". According to Wally's paper, if it cools a little it's not the compressor. The compressor clicks slightly but does engage. At idle, the air temperature is only about 58F. I have had the system charged with a weighed, correct amount. Any advice before I cook in the SC heat this summer?

Bruce Sinclair

Boyce , what sort of shape is your heater valve in? I have done some pretty extensive AC work on my car, I would be happy to take a look at it for you. I have one of the new griffith's compressors in my car. I also have a spare Nippondenso compressor that needs a clutch. If you need it you are welcome to it. I replaced it because I could get a new compressor for what a clutch would cost. My car will put out sub freezing temps at the center vent. A 928 with no AC is a miserable expirience in the summer in SC. Call me at 600 3470 if you would like to get together and take a look at your car.

Dozman

Should check the High and Low pressures when troubleshooting the a/c system. It may be a sticky TXV (Thermal Expansion Valve).

Tap gently on the body exterior of the TXV. This may or may not help you, if it is a sticky TXV.

Greg86andahalf

Boyce,

So many auto A/C performance problems can be tied to poor airflow through the condenser.

Check airflow through the condenser. Clean the condenser of road stones and debris (I had to carefully remove quite a few stones with a pick)

Use a garden hose to flow water through the fins from the radiator side.

Check fan clutch for proper operation.

Gotta have good airflow for the system to work properly. Do you have a gauge set?

Greg

Boyce

Bruce- I have no idea what shape it is in. Is that the same thing as the TXV? How do I check it? I am waiting to hear back from the A/C mechanic as to what the gauge levels read. I'm down in Charleston until Friday night but would love to get together sometime to talk about car stuff.

Greg- I don't have a gauge set. The condenser appears VERY clean. Not sure on the fan clutch. Thanks.

Bruce Sinclair

Boyce, I have a set of gauges, they will read to a certain range dependent upon ambient temperature. high side pressures can vary as much as 100 psi depending on ambient temperatures. The heater valve is different than the TXV. Get with me when you get back in town and we can go thru the troubleshooting procedures and find your problem. There are many factors that can have an effect on performance. Luckily most of them are pretty cheap and easy to fix.