AC Went out in my Forester Again

[SwampSurvivor]

Originally Posted by mk378
Compressor runs every time but only intermittently cools is probably a sticky expansion valve. The diagnosis is clear with pressure gauges, but like any intermittent problem it has to happen while the mechanic is there.


It runs with no refrigerant in it. I think that's the bigger issue.

But expansion valves are also problematic

 

[atikovi]

Originally Posted by Miller88
Originally Posted by mk378
Compressor runs every time but only intermittently cools is probably a sticky expansion valve. The diagnosis is clear with pressure gauges, but like any intermittent problem it has to happen while the mechanic is there.


It runs with no refrigerant in it. I think that's the bigger issue.


I don't believe that. All a/c systems I know of have a low pressure cutoff switch.

 

[mk378]

I was talking about LoneRanger's system which could blow ice cold, but only sometimes. If it gets cold once it has refrigerant.

 

[Saabist]

Originally Posted by atikovi
I don't believe that. All a/c systems I know of have a low pressure cutoff switch.


Many old R12 AC systems did not have a low pressure cutoff. These had compressors with an oil sump. For example, here is the wiring diagram for the air conditioning system in a 1962 Rambler American, not a cutoff switch to be found, just a thermostat and control switch:

 

[BMWTurboDzl]

Originally Posted by MParr
Keep the wife and dog and get a different car.

Keep the dog at the very least.

 

[SwampSurvivor]

Originally Posted by atikovi
Originally Posted by Miller88
Originally Posted by mk378
Compressor runs every time but only intermittently cools is probably a sticky expansion valve. The diagnosis is clear with pressure gauges, but like any intermittent problem it has to happen while the mechanic is there.


It runs with no refrigerant in it. I think that's the bigger issue.


I don't believe that. All a/c systems I know of have a low pressure cutoff switch.


If I press the schrader valve, nothing comes out; there is nothing in the system. But if I turn on the AC, the compressor engages and makes terrible sounds.

 

[SwampSurvivor]

New AC compressor and o-ring kit. Same as last time, AC compressor kept running with nothing in the system and burnt itself up. It doesn't make grinding noises anymore!