AirCon runs cold but fails after 5-10 mins - 2000V70

[Buck380]

Gareth,
If you're running R-134a, your low side pressure should be between 10-33psi while the clutch is engaged, max air and blower on high...or close to it. If its lower during the cycle, you likely have a restriction. (look for frost). Stays high, air flow at condensor or air in the system maybe.
-Buck

[ycmike]

Yep, my V70 does this too.
The low pressure switch will cut the clutch off at 22 psi as it's supposed to if the refigerant charge is too low.
With mine I discovered the gap between the clutch plate and the pulley was way too much. It should be a max of .020, but mine was more like .045.
I did a check at the pull apart connector on the compressor and found I had voltage there, but the clutch still wasn't engaging.
I read in another forum that to prove whether the clutch would engage or not the trick was to tap on the clutch plate with the ac turned to max cold and engine running. This will close up the gap for an instant and the clutch will engage. This is really silly and dangerous, but it does prove the theory.
I would say if the gap is .020 or less then it should work ok.
I don't know why it always works when cold for the first few cycles- perhaps the coil gets hot and loses efficiency.

[paplip]

Furball, any update on your problem? I have the same car and the same problem. Brought it to the dealer where they flushed and recharged the system with blacklight refrigerant and on the next visit, they told me it was the evaporator leaking. I don't know if I should beleive that since it always works for 10-15 minutes when the engine is cold enough.

I had read least year that it could be a temperature sensor on the compressor that was faulty but can't find that post anymore.

Thanks,
Patrick

[MadeInJapan]

Someone on Volvospeed had a write-up on how to decrease the clutch gap but I couldn't find it. Here is a thread with information though that you might find helpful. Evidently a good reputable A/C shop can take the washers out and decrease the clutch gap!
http://volvospeed.com/vs_forum/lofivers ... 21158.html

[Ozark Lee]

Furball,

I'm not sure if this is the same thread that MIJ has or not but it is a good discussion on the compressor shims and the thermal cutout. See the PDF writeup about midway through the thread.

http://volvospeed.com/vs_forum/Ac-Therm ... 76833.html

Jumpering the compressor without the engine running will cause no harm but don't leave it that way.

If it won't engage, even with a little coax (don't try that while the engine is running), your clutch is bad.

Best of luck and watch out for the buggers in stolen Mercedes sedans.

...Lee