My 96 850 turbo air conditioner cuts out after a few minutes of highway travel - the air blows cold and if the vehicle idles or the RPM stay below 2000 the air seems to work normal - I have an climate control system so the only A/C control on the panel is to shut the air off. If I shut it off on the highway for about 10 minutes it will start and I can here the compressor cycle a couple of times and it shuts down again. Any ideas on what I need to look at?

 

I would look at the compressor clutch gap. It might need to be reshimmed.

 

I'll bet low refrigerant. The higher the engine speed, the greater the volume moved by the compressor, and the lower the low side pressure. When the low side pressure gets too low, there is a switch to shutdown the compressor to prevent damage, and it is most likely opening, and shutting down your compressor.

- Tim

 

I stand with Tim.

 

Well, I serviced the ac in my wagon yesterday. Drove around a little and the air worked fine (just a 10 minute drive). About 3 hours later I drove about 5 minutes and then let the car sit parked idling for about 10 to 15 minutes while I talking to one of my friends. When I got back in the car the air had stopped. So I went where I was going and stayed there about 20 minutes. When I got back in the car, cranked it up, it started working again. Worked for about 10 minutes and stopped again.

Any ideas?

 

A couple of other A/C links:
https://volvoforums.com/forum/volvo-...highlight=cuts

https://volvoforums.com/forum/volvo-...up-my-ac-1905/

 

I have that exact same problem but sometimes when I turn mine on it doesn't get cold at all

 

Well, I've been driving the car around more and it's strange the way the A/C has been working. I drove 38 miles and it worked the entire trip. I drove 15 miles back and I pressed the gas kinda hard to pass a truck and the A/C went off, kinda like it was cutting off to give me power to pass the truck then did NOT come back on. I cut the system off for 10 minutes, turned it back on, and it worked for the rest of the trip home.

Got in the car an hour later to drive somewhere else and it did NOT work at all. Got in the car to drive 5 miles and it worked the entire trip. Got in the car to drive it 15 miles and it worked for 10 minutes then cut off and would not come back on. This random stuff makes it hard to pinpoint what's wrong. I then stopped for about 15 minutes, got in the car, and it worked all the way home. Just random.

 

Does the lit-up snowflake on your AC switch go out when it's not working? If yes then ck the switch itself..

 

A few people had a problem with the fan relay.
https://volvoforums.com/forum/volvo-...topping-56408/

 

Here are good instructions on how to test the fan relay.
https://volvoforums.com/forum/volvo-...ser-fan-55607/

 

I had a similar condition with my 850, the compressor was cycling on and off and the air from the ducts was just slightly cooler than ambient. I put in a can of freon and it works fine now. I just hope it's not a major leak!

 

More info on my problem. https://volvoforums.com/forum/volvo-...eration-56553/

Quick AC shim solution: My A/C Clutch Shim Fix - Volvospeed Forums

 

Did the quick fix and I'm up and running cold.
https://volvoforums.com/forum/volvo-...e2/#post285225

 

got that same issue. been trying to make it through this heat and then fix it. I usually turn off the ac if I am planning on stepping on it.

 

Hi guys, I have same problem with my a/c. After traveling 20 minutes or 1 hr and I have to stop at a gas station, my a/c does not work any more. Back to my home after 5 hrs (cold motor) my a/c back to working perfect. I did reshimming .015, freon 48 psi, no leak, but I do not know where is the problem. Any advice?

Thanks all.

 

There is a simple test you can use to determine if the clutch gap is too great: When motor is running and ac is on max. cool and compressor not engaged: Uaing a broom handle or similar, carefully reach down to the compressor face pulley. Carefully push against face pulley with the broom handle> If the compressor clicks in and starts cooling, the clutch gap is too great. Mechanics may advise removal of compressor and reshim clutch; however, working from below, I cleaned the small round spacing tabs that keeps pressure on the magnetic clutch gap to within 30 thousands/inch and epoxied ( some use crazy glue) an approximately 20 thousands thick piece of rough sanded formica ( some use plastic bread sealer wrapper sealer clips) under each tab. This brought the clearance to well within specs. and the compressorr worked. Also, there is a simple pressure gauge type item available at auto parts store one can use to check the coolant pressure; however, one can usually tell if there is insuffient, by checking the (large) coolant return line to compressor. If suffient coolant is installed, this line should be dripping condensed water and feel cold.

 

Thanks for your info, I did all thoses steps and also changed cooling fan relay ( from junk yard), but still the same problem.
Is there any other relays, connections or wires that I should check?
I am getting tired of the situation in my car because I have checked everything I know that could be the cuase of this problem. It's really a mystery.

 

Does it work if you bump the front of the compressor with a broom handle?

 

Two questions: What is the temperature when this happens, and is it running or not when you see 48psi? 48psi is not bad running, but if you only see 48psi *NOT* running, then you are low on charge. My 850 has failed to cool twice since new when it was very hot (2 years old, and last year), and both times it was low charge . . . not that other things can't happen, but AC hose and compressor seals are always a bit porous, so a small loss of charge over time is to be expected.

- Tim