W108 Air Conditioner Question - PeachParts Mercedes-Benz Forum

jmatcovich · #1 07-25-2015, 12:25 AM

I'm replacing most of the components of my AC system in a 1970 280SEL -new compressor, receiver-dryer, hoses, and expansion valve. Only the condensor and evaporator will be re-used. The system had not run in years and was leaking, had sludged up oil, and did not hold a charge. My question is 'how much refrigerant OIL goes into the entire system before putting the refrigerant in? And I'm sticking with R-12 if that makes a difference. The instructions on the new compressor say to 'not exceed the maximum amount of oil listed in the vehicle service manual.' Does anyone have that number?
What I've heard from a number of sources is that the typical amount of refrigerant oil in an AC system is 4 oz., but when we drained the new compressor before installing it, there was probably 3 times that amount in it. It has me scratching my head and wondering.

Thanks!
John

Idle · #2 07-25-2015, 02:12 PM

Given that the age of your car is 45 years it is a good bet that along the way, when charging the system, previous owners put in a charge of refrig, oil and stop leak. If so that would account for your excess oil.

The factory manual says that all systems (there were three different compressors used in the 108) require, upon a rebuild, an oil charge of .3 liters. That's 10.144 fluid ounces.

It is quite important to use the correct oil for R-12. Mercedes just says to use the correct oil and to refer to the specs but I cannot find the specs listed anywhere in the manual.

I think the place you buy your parts from can tell you the correct type of oil. I always just used a good mineral oil. The manual does say to 'never use machine oil or engine oil' so I guess the 3-in-1 oil is off the list.

Hopefully this helps.

billhard · #3 07-26-2015, 01:14 PM

Here is a PDF file of the service manual section titled "Checking the oil level of refrigerant compressor" hope this helps.

Bill

JimFreeh · #4 07-27-2015, 06:53 AM

Doesn't this car use the York compressor with the internal sump?

My 71 250C does.

Jim

Idle · #5 08-01-2015, 03:46 PM

Quote:

Originally Posted by JimFreeh

Doesn't this car use the York compressor with the internal sump?

My 71 250C does.

Jim

Some do, some don't. I have never seen a 108 with anything else but according to the manual it could use one of three different types.

I think it depends a lot on which country you bought your car in.

And the pdf shows how to isolate the system and check the oil in both of the positions in which the York can be mounted.