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Oil amount and type

GeorgeG on Mon July 09, 2012 10:24 AM User is offlineView users profile

Year: 2002
Make: Cheverolet
Model: Blazer
Engine Size: 4.3L W
Refrigerant Type: 134a
Country of Origin: United States

The compressor clutch went out at 185,000 miles. Recovered the 134a. Replaced the accumulator, orifice tube, and compressor (new AC Delco). Oil looked good, no debris in the orifice screen. The repair manual and compressor instructions said to pour the recovered oil amount plus 2 ounces into the new accumulator so I added the 1.5 oz recovered plus 2 = 3.5 ounces. Then I added the specified amount to the new compressor which was the greater of the amount recovered (which was minimal) or 2 ounces = 2 more ounces. Hand turned the compressor 15 times. Total oil added = 5.5 ounces. System spec = 8 oz.

Pulled a vacuum for 1 hour, held a vacuum for 10 min, broke the vacuum with 134a and charged to the 134a tank pressure. Started the truck/compressor and dumped the total weight specified by the system spec. Pressures were all good and the vent temp was 40F at 85F ambient. Compressor is somewhat noisy, a groaning sound when engaged. The cooling dropped off for a couple of weeks (50F at the vent) but then climbed back down to 42F or so at the vent.

Was this the correct amount or is there the possibility of excess oil in the system given that I recovered 1.5 ounces and added 5.5 ounces? Why do you add so much more than is recovered when the the amount of oil in the system is critical?

Also there was the whole debate of PAG150 like the old days of the Harrison H6 compressor and the tech bulletin for the change in GM oil to what I understand is now PAG46 oil. I called GM, independent distributors and anyone who would listen trying to get to the bottom of the PAG46/150 debate. A master tech at the Chevy dealer does not even use the GM oil but instead goes out to a local supply house to get PAG150. The compressor insert did not specify. I used PAG150. Was this correct?

Edited: Mon July 09, 2012 at 10:29 AM by GeorgeG

GeorgeG on Wed July 18, 2012 9:16 AM User is offlineView users profile

Forgot to mention that I confirmed that the new compressor contained only assembly oil before I added new oil.

TRB on Wed July 18, 2012 1:50 PM User is offlineView users profile

Front A/C only 8 ounces is the oil capacity.

Front & Rear A/C 11 ounces is the oil capacity.


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