A/C recommendations for the MB vehicles - PeachParts Mercedes-Benz Forum

vstech · #1 04-17-2011, 09:09 AM

Quote:

Originally Posted by leathermang

The MB AC FSM suggests as you put the system together... spacing out the total oil you are going to use in several places.... so that the entire burden of getting it spread around is not borne by the refrigerant..
This is ESPECIALLY IMPORTANT ON SYSTEMS USING THE R4 Delco since it is totally dependent on refrigerant carried lubricant.... lacking an oil sump itself..unlike most other AC compressor models ... even earlier models like the York..

yup. this will certainly aid the distribution of the oil into the system, but!!! it will not flow in nitrogen, so it will not coat all the seals and surfaces of the lines etc without the refrigerant charge.
my point here is on the OP's statement of his system not holding vacuum until the oil got into the system,,, it's not important for a pressure test. it is CERTAINLY important to have the exact volume of oil, distributed during installation of the components in the quantities specified in the FSM.

vstech · #2 04-18-2011, 06:04 PM

Quote:

Originally Posted by Hit Man X

Hmm, so do I just vent the Nitrogen? Then carry on the charging process as normal?

yes.
after verifying no leaks are present, vent the nitrogen, then attach your vacuum pump, and evacuate the charge, and refill with the correct volume of refrigerant.
I use 30 lb jugs, of refrigerant, so I can charge with the system OFF, the correct volume into an evacuated system.
most DIY types need to use 12 oz cans, and each time the can is opened, air gets into the manifold, and the car, and some of the refrigerant is lost.

to properly recharge a system, a reclaimer is needed, and a charging station, or at least a jug of liquid refrigerant, and a scale...