Okay, this just started earlier this week, and of course it starts happening when we have 100 degree weather...

My A/C in my '96 850Rintermittently stops working for abot 20-30 seconds, and then will start working again. Here isa scenario...Leave work at 1530, turn A/C on. It works flawlessly (ICE FREAKING COLD)the 15 miles in a mixture of stop and go and 50mph "highway" speeds. I shut the car off when I arrive at Target to pick up some supplies. I'm inside for approx. 15 minutes. After starting the car, I turn the A/C on again. it blows cold for about a minute. Then, next thing I know, warm air for about 30 seconds, then starts to blow cold again for several minutes.
Sooo...then, I work on this house for about a hour and a half. After leaving, turn the A/C on, and it works flawlessly for the 15 mile drive of part highway (60+ mph) and stop and go. NOW, on the drive home on the highway, one thing I did notice was an occational "hickup". I niticed it more often on deceleration, the car would seem to have a momentary (for for a second) loss of power, and slow down more rapidly that normal when decelerating (I say decelerating....but it's more like "feathering" the gas to maintain a constant speed of 60mph). I've turned on the cruise control to see if this same thing would happen, and I did not notice it. Also, I do not think I've felt the same thing with the A/C off.

I have not heard any abnormal noises. I'm wondering if I'm having an issue with the electronic clutch on the compressor. This is not an issue of freezing up (low refrigerant), and it would not start working again so quickly (it also wouldn't freeze up and stop working as quickly as it does, either).

 

Sounds to me like your A/C compressor clutch gap might be out of spec. When the clutch plate wears with age the space becomes too large and on hot days the clutch won't engage well. There are shims that can be removed to tighten the gap and fix this problem. There's a great write up on this from volvospeed.com..... Here's a link to the .pdf file. This doesn't explain your loss of power issue, but I still thought it would be worth offering this suggestion. You can measure the gap quite easily using a set of feeler gauges. The linked .pdf file explains it all in detail.

My 850 Turbo has this problem and I plan on trying the fix this weekend. I made a template in AutoCAD (.pdf file) that I am using to make the custom tool needed to pull the clutch plate from the compressor. I plan on printing it out and using it as a guide to drill the holes. Let me know if you'd like me to provide the template.


Good luck!

 

Custom tool? Which one would that be?

 

The idea is that this "custom tool" allows you to thread some metric bolts into the compressor clutch plate to pull it off the shaft. It is just a metal plate with holes positioned to align properly with the holes on the compressor clutch plate. I guess an actual gear puller might work if you had one and you could fit it into the engine bay. Since I don't have a gear puller I really don't know. The .pdf I linked to in my first post describes the tool in more detail. It tells you specifically which metric bolts you need and thedimensions and layoutfor the holes.

 

Thanks for the input guys. I'm going to check the clearance on the clutch shortly.