Question for a/c gurus

[dragrazor]

The a/c in my GN hasnt been cooling very good so i had a friend who mostly works on commercial machinery bring gauges and freon just in case my car was low on freon. I'll try to explain what he told me he saw:
The low side started creeping up to 60psi and it should be around 40psi and the high side barely reached 170 to 180 psi.
He said that the high side was fine but that the low side pressure was too high so he released some freon to bring the pressure down but now the a/c is not as cold. The a/c got cooler inside after he added the freon and the dryer got really cold but since the pressure got too high, he released the freon to bring down the pressure. He said that he thinks the compressor might be going bad. The clutch stays engaged all the time. The car has been changed over to r134. Inwas told that a new dryer and orifice tube were installed when retrofitted. Is the compressor going bad? I have intrepid fans also so the air going over the condensor is good. Let me know if inam forgetting anything, i'll try to answer it. Thank you in advance.

 

[achalmersman]

personally I dont charge anything by pressures. Too much variance. The only way to know for sure if its got the correct amount is to recover it and weigh it. That's where I start if I believe the charge to be an issue.

 

[6cylboost]

high suction low head is usually an inefficient compressor. I have a panic attack if pressures dont have at least 100 psig spread

 

[dragrazor]

Gonna do that then, recover it and weigh it, before ithrow parts at it. Thanks.

 

[Wahoo]

Did you have the blower on highest setting?

Its inportant to do that when checking the pressures, also have to get the rpms up to 1500-1750 as well.

 

[dragrazor]

Did you have the blower on highest setting?

Its inportant to do that when checking the pressures, also have to get the rpms up to 1500-1750 as well.

Yes, it was on max a/c and the blower on high. I also accelerated the engine and the pressure came down a little but when i let the engine idle, the pressure came back up.

 

[Wahoo]

Yes, it was on max a/c and the blower on high. I also accelerated the engine and the pressure came down a little but when i let the engine idle, the pressure came back up.

Thats normal from what i have seen. But its been awhile since i worked on automotive.


Generally the low side drops as rpm comes up, highside increases as well.

 

[69RSCLONE]

Low air flow over the condenser will cause the same pressure discrepancies. Is the cooling fan running? Place a fan in front of the condenser.

Another thing, orifice tube could be damaged and not restricting the flow correctly, but not common.