The A/C on my 850 works well for a while (15 min), but then shuts off and will not turn back on unless I shut the car off.

I just swapped out the A/c compressor because the old one had seized up. The system still had some pressure in it when I took it apart but I don't think it was fully charged. I took it in to a garage to be charged up. They evacuated the system, added oil, a small amount of sealant, and some leak detector before charging it up. They warned me that it would have been best to have also changed the drier, but thought that it would probably be OK since it was only apart for a short time.

Thanks for the help!

Pat

It may be low voltage getting to the clutch. You can check it out with a VOM connected to the clutch and sitting on the pass seat. I found the volts dropped to less than 11 and the clutch could not pull in. I put a relay in the circuit. and all is well now. Here is what I did.

First you need to locate the wire to the AC clutch. Follow it back from the clutch and you will find a small square box, this is the thermal limiter. It is not needed and is a problem area. Take the wire from before the thermal device (the wiring harness side) and extend this with a few feet of wire and take the wire from the other side of the thermal device and extend the same way. These wires will hook up to a relay(Std Bosch or Hella foglight type relay). This can be mounted any where you decide to put it. The wire going TO the compressor (The wire from before the thermal device) is the trigger wire for the relay. You will need a power source for the load. I took it from the battery. Dedicated wire with a fuse. The other compressor wire is load. This will give you full battery voltage to the clutch. When I did this over 2 years ago my mechanic thought it was a good idea but how much time will you get? And is it really worth it? So far well over a two years of 50 miles a day.
I'm not the best at describing things in writing. Hope this helps.
Any other questions, please ask.
--
Howard Berman 2002 V70 90K, 95 850 wagon 162K, 2000 S80T6 72K, 94 850 Sedan 140K, 68 1800S 80K(My Toy)

Wise man at the shop, the dryer/accumulator did need to be replaced, it gets garbaged up over the years and can get prone to leaks. Next time you go in for a charge...

Now, be brave. If the clutch on the compressor has too large a gap, it will not engage when hot. So start up the engine or when you come home and the AC no longer "works", look at the clutch and see if it is spinning.
If not, then using a short broom stick, carefully tap the clutch towards the compressor. WARNING, the clutch will start spinning and you don't want to touch the belts or other moving parts!!! If the clutch engages, then the gap is too large.
The permanent fix is to move a shim or two from behind the clutch to infront of the clutch, depending on the gap. There is another temporary fix:

http://volvospeed.com/vs_forum/index.php?showtopic=80181


Klaus
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I still miss my 164 and my 854T. Just driving a V70R :)

Well, it looks like another correct diagnosis by Klaus. I drove the car until the A/C quit working (it took quite a while this morning, maybe because it was cooler?) and then tried your broomstick test. As soon as I pushed on clutch just a little bit it engaged and stayed on.

The bread clip repair looks pretty cool. I'll probably try that first.

The official fix must require the removal of the A/C clutch. How hard is it to get the A/C clutch off without removing the compressor? I'd hate to have to pay for the recharge again!

Thanks,

Pat

Removing the clutch is a PITA, but doable. There are write ups for that over on Volvospeed for DIY. No coolant is lost in the process.

Have fun with the bread clips!!

Klaus
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I still miss my 164 and my 854T. Just driving a V70R :)