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AC compressor knocks at higher pressure

TEB65 on Sun September 07, 2008 9:16 AM User is offline

Year: 2002
Make: oldsmobile
Model: intrigue
Engine Size: 6 cyl
Refrigerant Type: 134a
Ambient Temp: 80
Pressure Low: 25
Pressure High: 180

After replacing the compressor, while adding refrigerant the compressor began to knock. I had added the correct amount and type of oil and evacuated the system and tested for leaks. the system should hold 2.2 lbs but after adding the first can of 134a ( as the pressures are coming up) the compressor begins to knock. At first I thought the clutch was hitting something (sounded like a card in a bicycle spoke). If I leave it low on refrigerant the knock will only be there for about 10 seconds, but if I try to get close to the full amount it makes the sound constantly. I have tried a couple of times to evacuate the system and start over incase I missed something but it happens every time. with about 2/3 of the charge in it is putting out some cold air.

mk378 on Sun September 07, 2008 10:11 AM User is offline

Did you put your oil into the oil sump by opening the plug in the side of the compressor? That's where it goes. Pouring it into the lines will leave most of the moving parts of the compressor dry.

TEB65 on Sun September 07, 2008 10:22 AM User is offline

I poured into the "sump". It says it does not have a sump but to pour it into the hole on the side then rotate the compressor by hand about ten revolutions.

GM Tech on Sun September 07, 2008 12:33 PM User is offline

Sounds like a full stroke knock-- who was the manufacturer? was this a new pump or a rebuild? Sounds like you should exersize your warranty..

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

TEB65 on Sun September 07, 2008 12:45 PM User is offline

It is a Ready Aire remanufactured pump. I don't mind taking it back I just mind taking it off. A lot of stuff comes off prior to removing the compressor. Looking at other possibilities first.

Chick on Mon September 08, 2008 10:29 PM User is offlineView users profile

Since you can't run it without the full charge in it, (that'll burn the compressor out fast) then I agree with GM tech, return it..

Email: Chick


Freedoms just another word for nothing left to lose

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