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Faulty Compressor or something else

AcMoron on Sat October 17, 2015 11:13 PM User is offlineView users profile

Year: 2003
Make: Subaru
Model: Frankenstein
Engine Size: 3.0
Refrigerant Type: R134A
Ambient Temp: 82
Pressure Low: 110
Pressure High: 0

I've installed an AC system in an old car and need direction. All parts, hoses, fittings, you name it, are new except the compressor which came on the engine. I pulled a vacuum on the system for 45 mins then let it sit to confirm it wasn't leaking. Next I added appx 10-12oz's of R-134A. It wouldn't take any more! The pressure on the low side climbed to 110psi but the hi side never showed any pressure. The compressor would not kick in because the binary switch would not pass the current. It's specs are Low opens at 28 /Hi opens at 454 & closes at 369. Is this correct or even close to being correct? And why didn't it let current pass? I jumped the Compressor clutch but the pressures remained the same. Does this mean the compressor is defective? Thanks

Dougflas on Sun October 18, 2015 7:35 AM User is offline

It is possible your high side hose is not pushing on the shrader valve. remove the hose and use a tooth pick or similiar to push in on the shrader for a second or two. It should be under pressure.

AcMoron on Mon October 19, 2015 12:18 PM User is offlineView users profile

No. It let most of the can discharge into the low side. Any other suggestions???

EDIT: Let me change that to yes. I was wrong. A combination of old eyes and a Chinese suction port. I never had the adapter fully seated on the port and was dumping Freon. Now I need the ambient temps to get back to the 90's. It was 80F when I did this. I'll probably have a few more questions next week but I'm happy to know things are working. Thx for the help, Guy's.

Edited: Wed October 21, 2015 at 3:06 PM by AcMoron

bohica2xo on Tue October 20, 2015 10:33 AM User is offline

BOTH couplers are failing to depress the schrader valves. You said you pulled a vacuum - how long did it take to pull down?

You can push refrigerant past the low side schrader if it is not depressed - it acts like a check valve. The low side pressure you see is whatever refrigerant is trapped in the hose - not the system pressure.

Your high side will not read if the schrader is closed.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

AcMoron on Wed October 21, 2015 3:10 PM User is offlineView users profile

You nailed it. Took me a few hours to discover my error. Cheap set of gages and a Chinese port that is a bit off size to boot. I'll post my gage readings, as soon as we get a 90F day, for your input. TIA, Kent

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