AC goes warm at idle

[3D914]

I've noticed on my 87 - 924S that the AC goes warm at idle. Is there an idle compensation that disables the compressor, or is this something more sinister?

[Razorback1980]

Not real familiar with the 924 but I'm pretty sure it's more sinister. Two things will cause this to happen...inadequate freon and the clutch not staying engaged or slipping. Check your freon first as that's an easy one and most likely to be it. If it checks fine, then take a volt reading on the compressor wire to make sure it's reading a full 12V. If not, look to the a/c relay. If there is 12 Volts there, then the clutch is probably going bad. That would be the order I would check things anyway.

[3D914]

Thanks for the reply Tom,

Didn't check the voltage yet - that's a good idea. Actually the AC setup should be close to the 944, since this is an S with the 944 engine.

It also feels like there is some heat coming in near my feat (at all times while AC is on). I have the controls set as suggested in the manual for AC use, but something else is going on.

Still puzzled . . .

[Razorback1980]

OK...here you go....Sorry, I should have had you check this first...

http://www.kronowit.com/porsches/944-heater-fix.html

[Trevor]

Are both of the cooling fans working?

[3D914]

Thanks again Tom,

Both fans are running as I recently replaced the thermal switch.

I thinks there are two things going here: 1) the AC output warms up at idle & 2) there is heat being output at the floor. I'll look at both this weekend . . ,

especially since I now have to replace the *@$^(*@(-ing $60 AC adjuster arm - again.

This is the second time the eye-bolt has sheered off. I didn't mind the first time since it was probably the original part, but the new one has only been on for a couple of weeks.

THis is not a good way to start off a relationship with a new (used) car!

[Razorback1980]

There must be a reason why the eye bolt is shearing. You may want to check the position of the a/c compressor....does it look straight? It almost sounds like the compressor is pulling at an angle which is putting sideways pressure on the adjuster. Check the mounting of the compressor and make sure both ends are securely fastened and can't move other than swing for adjustment. That may be why it gets warm at idle as well...the compressor is moving sideways and the belt is slipping. A person can't be without a/c where you live. Let us know what you find.

[3D914]

Tom,

That's exactly the process I went through after the first one broke. Found out that the rear pivot stud had sheered as well. I had to drop the compressor enough to get back there and thread out the remaining stud. Replaced it with a new stud, checked the front pivot bolt, and installed the current adjuster arm. Two weeks later - snap again!

It is possible that the rear stud has sheered again as well. I just haven't had the time to get out to the HOT garage to check - been nursing sick wife.

I'll keep ya posted.

[AFJuvat]

Look for a vacuum leak.

AFJ

[3D914]

Well . . .

it turned out that the new threaded stud I put in for the rear pivot point backed out completely - this also caused the front pivot bolt to shear along with the adjuster eye bolt.

So now its just a matter of getting the replacements tomorrow, then I can continue to check everything else.

THanks guys,

[Razorback1980]

Good find...and good luck....use a high grade bolt as the a/c is a pretty hard pull and if it's not straight, it's going to break some things. It's almost impossible to shear that eye bolt if the compressor is pulling straight...pulling sideways, it's relatively easy, so if it's broken, that's an indication the mounting bolts are loose or broken.

[AaronM]

On my car, I get less cooling at idle (still cold, just not as cold). The A/C needs about 2,000 RPM to be performing to spec. Chances are that you're just low on refrigerant.