Automotive Air Conditioning Information Forum (Archives)

idickers on Fri October 11, 2013 2:45 PM

Year: 1991
Make: BMW
Model: 318is
Engine Size: 1.8 L
Refrigerant Type: 134a

I just finished up repairing an older a/c system and converted it to 134a. Now it's time to fill, except that I forgot to add the oil to the evaporator and condensor while reassembling. I've got 2 oz in the compressor, and the specs call for 4 more oz, and my question is how to add it?

I have a Mastercool Universal dye/oil injector, and according to the instructions I can use this to add oil to the low pressure port. I'm assuming this will inject oil through the schrader valve in the low side port? If I pull a good vacuum on the system, will the vacuum sufficient to pull in the oil? Can I add the 4 oz all at once, or do I need to space it out to avoid seizing the pump?
Thanks in advance for any suggestions!

GM Tech on Fri October 11, 2013 7:38 PM

Suck it in with your vacuum pump- all oil comes in the pump at the factory assembly plant- so oil distribution is not necessary.

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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......