A/C Oil Question - PeachParts Mercedes-Benz Forum

sjh · #1 08-14-2011, 06:29 PM

Greetings.

My car '90 300D om602.962 has the stock A/C unit. The PO converted to 134a. The job seems to have been correctly and the car cools well up to 90 or so unless the radiant is very bad.

Here's the question.

I'm thinking about having my A/C friend 'suck' the 134a with his reclamation machine. I don't know how perfect a vacuum these systems obtain but let's assume it gets down to 5" Hg.

Is the oil 'sucked' out as well with these machines?

If I was going to put 134a back in would I need to add oil?

How is all of the oil removed from the system?

Thanks.

.

engatwork · #2 08-14-2011, 06:48 PM

A little oil will be reclaimed with the refrigerant. On my machine I am able to capture the captured oil into a bottle on the machine and can measure how much has come out with the refrigerant. This tells me how much I need to put back in.

Oil is removed from the system by disassembling everything and all the connections and flushing the system with the exception of the compressor and condenser. You drain the compressor by holding it up with the nozzles facing down over your drain pan and turn it. The p-flow condensers will flush out but with limited success because of the close tolerances in the passages.

sjh · #3 08-14-2011, 08:04 PM

Thanks Jim.

I thought the oil wouldn't be very volatile and so would stay within but I wanted confirmation.

.

engatwork · #4 08-14-2011, 08:20 PM

For the most part it does. I can say that it is typically 1/2 and surely not over 1 ounce that I recover in the machine when I evacuate a system with say, 2.2 pounds.

vstech · #5 08-14-2011, 09:06 PM

it really depends on the type of recovery machine used, some newer ones can pull liquid and vapor, and those can actually pull the oil from the condenser, I've gotten over 4 oz in some recovery jobs.