1985 300D AC compressor change - Page 2 - PeachParts Mercedes-Benz Forum

Mercedes Man · #16 07-06-2003, 01:46 PM

I can see leathermag's confusion. The R-4 compressor says 6 oz or .17 kg of refrigerant oil!

I always thought that refrigerant oil was a liquid measure.

ATLD · #17 07-06-2003, 01:58 PM

Mercedes Man,

Is the picture that you attached of a new or rebuilt compressor; I got one that's unused and marked identically off eBay really inexpensively; it was sold as "NEW" and "not rebuilt" so I'd like to verify this?

Thanks,

ATLD

P.S. Most capacities when referring to refrigerents are done by weight (at least for home AC systems), as the volume is purely dependent on pressure and can easily change (hence, even if two identical cans are full to the same capacity, the mass of freon contained might vary considerably between the two). This isn't applicable for oil, but I'd guess that they would be consistent when working with an AC system.

Mercedes Man · #18 07-06-2003, 02:45 PM

ATLD,

This is the link to the eBay auction I found the picture on:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2422504856&category=33543

You can judge for yourself, but he says it is new.

Have people been making a big mistake by using a measuring cup for oil?

Mercedes Man · #19 07-06-2003, 04:45 PM

Perhaps I should say that 1 fl oz of oil roughly equals 1 advp oz of oil.

funola · #20 08-10-2016, 08:59 AM

Quote:

Originally Posted by Mercedes Man

Perhaps I should say that 1 fl oz of oil roughly equals 1 advp oz of oil.

In other words, 1 oz of oil by volume is very close to 1 oz of oil by weight. So you can weigh the oil with a scale, or use a measuring cup, results will be close enough to each other.

Mercedes Man · #21 08-18-2016, 10:37 PM

I ended up buying a rebuilt R-4 compressor but it started making some knocking noise a couple of years later. That compressor was replaced with a brand new R-4 compressor.

The oil fill for the R-4 system was:
compressor - 4 oz
condenser - 2 oz
evaporator - 2 oz

These are fluid ounces.

4 oz is a lot of oil, so you have to be careful not to dump it out when mounting the compressor. Some of the oil wants to drip out when putting the lines on. The new compressor has been very quiet compared the old R-4 compressors of the past. I would never buy a rebuilt compressor again. It is best to spend the extra money for a brand new one.

leathermang · #22 08-19-2016, 02:45 AM

Quote:

Originally Posted by Mercedes Man

.....

The oil fill for the R-4 system was:
compressor - 4 oz
condenser - 2 oz
evaporator - 2 oz

These are fluid ounces.

4 oz is a lot of oil, so you have to be careful not to dump it out when mounting the compressor. Some of the oil wants to drip out when putting the lines on. .....

ALSO in the MB AC FSM they are very specific... If oil is added to the compressor... it is to be treated like a new compressor.. IE... run for four minutes at IDLE before increasing the rpms....