R4 compressor - what would you do if you were in my shoes? - Page 2 - PeachParts Mercedes-Benz Forum

PackerEdgerton · #16 09-12-2012, 05:45 PM

All new R4 compressors have "Stepped Ports" on them. This is a fancy way of saying that in order to accomodate the many variations of cars that have R4 compressors, the designers of new R4 compressor units went with a design where the input/output ports are not on the same plane. The W123 A/C manifold is designed for a "Flat" port mount, meaning that the input/output ports are essentially flat and on the same plane.

In order to get the 'stepped port' R4 compressors to seal properly to the flat manifold of the W123, the new compressors have "Sealing Washers" of different thicknesses that are used to accomodate for the difference in sealing surfaces. The problem is that unless you read the instructions precisely or can figure it out through trial and error, many people have problems trying to figure out how to get the manifold sealed properly using the various sealing washers.

I hope this explains the problem.

Sincerely,

PE

ah-kay · #17 09-12-2012, 06:07 PM

I am not a novice on A/C, so to speak, so I think I know what I am doing. I have converted many cars to R134a with great success. I always add 8 oz of ester oil, in addition to whatever residual oil was in the system. Ester oil mixes well with all the residual oil. I normally do not flush the system and it seems to be OK during all my A/C repairs. That include conversion, compressor R&R, condenser R&R and evap R&R. May be I am just lucky but there is nothing to A/C. I always replace the recv/drier as a general procedure once I open up the system and it has served me well.

The R4 is a pain in the a$$. The oil drains out when you install it as the port is on the side. The port washer is fiddly etc etc. I am getting very good results with this R&R. I have cold air except I just find the compressor noisier than I like. I can 'hear' it running which I find it undesirable. Would it do any damage? I do not know. The seller offers to swap it out for free but it is a Royal pain in the butt to do it once again. So I am going to leave it until it goes kaput again.

I read all the postings here and it seems that the R4 is not a very good design and inherently noisy. May be mine is more noisy than the norm. Would I change it to the Sanden one? Possibly but I am fed up with car repair for now. I need more time on the golf course.