My airconditioning dies when I accelerate. I can't hear the compressor because 960's are very quiet, but the air flow stops coming out of the vents. Is there a check valve that may have failed? I repalced the head gasket right after buying it (the price made it worth it) and maybe I got the two check valves on the fire wall screwed up? This is my first nice Volvo so I am still learning.

 

Have you visually checked the compressor whilst the vehicle is stationaryand the revs are increased?

The EEC has a self diagnostic function. Have you checked for trouble codes?

 

I ran the check on the climate control and no codes came up. I think the system is OK, I feel that vacuum of some sort is the trouble. I have not visualy checked the compressor. I will do that tomorrow.

 

great first post

I have the same problem the a/c works just acts like the vent is closing as i am under a load the opens back up
a/c never stops fan never stopped just closes the vents. It does not seem to matter if i am in auto or just setting it

 

I had this exact problem on a 960. If I remember correctly, it turned out to be a bad actuator door that was powered by vacumn. It would open under acceleration basically diverting the cool air away from the cabin.
It was so common that someone posted an how-to-fix on one of the Volvo forums (think it was this one). Because you want to avoid taking the whole dashboard apart, they came up with a neat way to cut a little door in the air plentum under the dash with an exacto knife, repair replace the actuator, and close/seal the door. The proceedure came with great pictures. Its still a real pain but it worked for me.

I was also told the car had an A/C cutout for acceleration but I didn't ever verify this.

 

I had the same problem with my a/c. It would shift modes and stick on the defrost. No error codes were ever reported. It ended up being the vacuum solenoid went bad.

 

It usally re-directs the air to the floor when the dash pods ( those vacuum solenoids you talkin about) go bad. They are a pain in the a** to replace. Only did the job once on a car and hated it.