I have a 2007 XC90 with a V8.
The Air Conditioning has been working intermittently lately. My wife drives it and says that it'll work for a while, then stops. I have read many threads that state the solenoid in the compressor, or the compressor could be bad.
I did rent a manifold gauge from Autozone and took some readings today.
At first startup in the driveway, the A/C blew super cold and the pressure was at 40psi on the low and about 160 on the high side. The needles didn't move much. The high side fluctuated a little bit, but only about 5-10 psi. The compressor clutch stayed on all the time.
I took it for a drive and it worked great for 10 minutes. Stopped for gas and drove back home and it didn't work. I put the gauges on when I got home and the low side was at 50psi and the high was about 400psi. What? I didn't think it would ever get that high. The car was blowing ambient air, not cold. The radiator fan was spinning at a super fast speed also.
I opened up the high side valve in the manifold gauge for a split second and it dropped down to 300psi. Then fluctuated a bit and stabilized. I did it again and now it's back at 40psi on the low side and 200-220psi on the high side and blowing cool air again. When I did this , the radiator fan slowed down to what I would consider a normal speed. If I got the RPMs up to 1500-2000, it started blowing cold again.
What would cause the high side to go to 400psi? Is this a solenoid problem? Compressor problem? Something clogging the system somewhere?
I'd like to fix this myself and save money if possible, but could take it in if needed.