Automotive Air Conditioning Information Forum (Archives)

loritom62 on Mon March 14, 2011 8:19 PM

Year: 98
Make: chevy
Model: venture
Engine Size: 3.4
Refrigerant Type: r134

Hi,
I changed my compressor,orifice tube and accumulator of all these components i only managed to drain about 25 drops of oil.I was wondering if i should add more oil or just leave it like it is.The old compressor had a seal leak and lost all the r134. The new compressor already had 1.5 ounces in it.Thanks for the help.
Tom

GM Tech on Mon March 14, 2011 9:38 PM

Did you open the drain bolt from the crankcase of the compressor? There should have been nearly 3 ozs in there alone.

I have seen mechanics try to drain the oil from the V-5 compressor out the ports--not realizing there is a crankcase designed to hold oil.

Also, there is at least 2-3 ozs of oil soaked up into the desiccant bag of the old accumulator-- to be sure, weigh the old versus the new A/D. (if they are the same design)

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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......

Cussboy on Mon March 14, 2011 11:16 PM

Couldn't your oil loss be out that compressor seal ???

HECAT on Tue March 15, 2011 7:28 AM

Even with the V5 crankcase; oil migration becomes compromised as the refrigerant charge drops (leak). The critical oil migration point that requires a proper charge is inside the evaporator, and this is where the oils will often pool.

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NickD on Tue March 15, 2011 9:52 AM

Tis nice the sump in AC compressors was reinvented, some always stays in there to help prevent catastrophic failure that we have become accustomed to with the demise of the A-6.

But then also blessed with PAG oil that is made out of the stuff women slap all over their face with. If you want to see what PAG sludge looks like, don't have to go any further than your bathroom sink. Now I am wondering if I should swipe my wifes' facial soap to flush out my MVAC system with, seems to do a good job on her face.

But anyway, best to replace the dryer, drain and flush the compressor with fresh PAB, and flush out the rest of it. I like to draw a deep vacuum first before injecting the new PAG.

Payment for you doing this will be having a system that lasts more than two weeks.