Pag Oil requirement amount after upgrading?

[driller35]

Looking for the correct amount of Pag oil to add to upgraded system, Compressor 3.5oz (already added at factory) putting on new muffler hose , hose liquid line, accumalator drier, expansion valve, how many extra ounces does it require TIA

[68Gold/white]

My thoughts.... try to find the amount of refrigerant oil your system took from factory.
Or...
The general rule of thumb was 2oz for the condenser, 2oz for the evap, and 2 oz for the drier.
Sounds like a lot offer oil?

Anyone?

[Sheepdip]

My system was all brand new evap, cond, hoses etc so everything was dry except the compressor which had a tag that said it had 7 oz of oil added at the factory. I added another 2 oz of florescent dye oil. Been ice cold for 2 years now. I did look up at the time what the factory system had, and if memory serves me correct, I think it was 8 oz.

[Bigdav160]

OEM procedures usually have you drain, measure and discard the oil in the replacement compressor. Then add the proper amount of new oil depending on the service being preformed. Replacing compressor only (depending on the type of compressor) 1-2 ounces. Dry system that's been flushed would take several ounces of oil.

[driller35]

Thanks Guys much appreciated , reading some places it get contradictory as to the amount and obiviously the 3.5oz in the compressor is not enough Cheers

[Davidf]

I think 8 oz. of oil for a bone dry system would be about right. Somewhere close and you should be fine. Too much oil can reduce the efficiency of the system. I usually err on the lower side for oil...it does not take much. There is a reason (IMHO) most PAG oil containers are 8oz or less.

[68Gold/white]

Originally Posted by driller35

Thanks Guys much appreciated , reading some places it get contradictory as to the amount and obiviously the 3.5oz in the compressor is not enough Cheers

I've put maybe 20 compressors on. They all have oil but NEVER tell you what type of oil, so I drain oil out of the drain plug AND let the compressor sit vertical on top of an old coffee can to make sue most drains out. I put a close amount back where the plug was and some in the suction port.

BEFORE you re-install the compressor, set it with clutch end down. THis lets oil soak the seal, to hopefully insure no leaks on start up. THere's no gaurentee on how long a compressor has been setting on a shelf.......

[Davidf]

Also, it is very important to rotate the compressor (not just the pulley) by hand several revolutions prior to putting in service. This ensures the oil in the compressor will not cause a liquid lock situation and damage the internals.

PAG is more common that Ester and both are compatible, so it really does not matter what oil is in the compressor to begin with. Ester is probably a bit more moisture and mineral (if doing a R12 to R134a swap) oil tolerant.

[mrein3]

I put a stock system in my truck that I converted to R134a a long time ago. I forgot how much oil I used to I found the post and looked through it quick. Looks like I put in 11 oz.

You can read about it here:
http://67-72chevytrucks.com/vboard/s...d.php?t=478564

[driller35]

Thanks guys, found a truck shop manual with the necessary info, for me doing a flush , compressor, hoses ,air drier, 10 oz for the system in total for oil, hopefully all the rest of my parts are in tomorrow and can have up and running Fri AIR CONDITIONING SYSTEM CAPACITY
Refrigerant
Charge
. Oil Charge
Four-Season System 3 lbs. 4 oz. 10 oz. 525 Viscosity
Roof-Mounted 5 lbs. 8 oz. 13 oz. 525 Viscosity
GM Chevrolet 3 lbs. 4 oz. 10 oz. 525 Viscosity

[Richard]

I have done several 134a conversions and when charging start out at 15% less refrigerant than the factory R-22 charge. Used the same with the oil charge capacity.