V70 T5 Air conditioning

[dmole]

Three different garages have had a go at sorting this problem out, the main London Volvo garages have tried twice (at enormous expense). All have failed so far.

What happens is that the air conditioning comes on at first, blowing cold air. If the driving is the usual stop-start urban driving, it will fail in about 10 minutes. If the car goes onto a motorway where the speed hardly ever drops below 50 mph it will work all day. But as soon as the car slows or stops because of queuing traffic the air conditioning will fail. If it is then turned off and not turned back on until the speed is up to at least 50 mph, it will work until the next queue, village or traffic lights.

The garages have searched for leaks. I am told there are none and the gas is fully charged. The most recent (and most thoughtful) (country) garage has replaced the pressure switch. This appeared to work for a day, but then we were back to the same old pattern of failures.

Any thoughts?

[jda2000]

sounds like a compressor clutch gap problem.

do a search on ac compressor clutch gap fix

[dmole]

Thank you for your advice. DMOLE

[Retired MVS Contributor]

I suspect a sticking expansion valve, which is suppposed to automatically adjust system flow in accordance with engine speed...Since it works correctly for as long as speed is steady but acts up if speed is changed, I think it is sticking...Not all Volvos have expansion valves, but yours does...