R4 Compressor Quality - PeachParts Mercedes-Benz Forum

83TD · #1 04-01-2017, 04:58 PM

So I got my 83 300TD out of winter storage yesterday only to find that the air conditioning compressor would not engage, the pressure switch on the receiver was open circuit(i.e., not enough pressure to close it) and there were two large globs of mineral oil hanging on the bottom of the compressor just waiting to drop.
The oil was leaking not at the ports, which were nice and dry, but at the periphery of the housing where the steel band meets the aluminum housing--supposed to be sealed by o-rings. I can only assume that if it is leaking oil, it is also leaking refrigerant.

This compressor is a two year old one from CompressorWerks that I installed after the original one finally gave up the ghost.

I am reluctantly going to install another R4, keeping in mind a popular definition of insanity, but am wondering if there is any difference in quality among the variety of R4s available under different brands, some advertised as "new", others as rebuilds. Is the one from Mercedes that costs a lot more any better? I would be surprised that anyone other than CompressorWerks is manufacturing new ones, but there might be more than one rebuilder.

Any advice appreciated. Thanks.

Peter

tyl604 · #2 04-01-2017, 08:35 PM

I think Pelican has them for about$150

ROLLGUY · #3 04-02-2017, 09:57 PM

Even though Compressorworks is a US company, and manufactures them here in the US (Texas I believe), some or many parts may be sourced from China (can you believe that?). I also would not suggest a rebuild for the same reason. IF by chance you could find a Delphi, Harrison, or other NOS unit, that would be best in my opinion. However, it is possible that even those are made of Unobtanium. Whatever you do, get one with the best warranty, and follow the instructions to the letter. Even then, many suppliers will find a way to not honor the warranty.

BillGrissom · #4 04-03-2017, 03:58 PM

You can find photos online. The R4 has a large circumferential O-ring that seals against the outer steel shell on each end. It is common to get a leak there. One guy here posted photos of the steel shell slid back from the aluminum body, which caused the rear O-ring to extrude. The only thing that secures the shell is that sheet-metal tab. I bought a new R4 on ebay for < $50 a few years ago. Installed it last Fall when the custom Sanden bracket cracked and still holding. But, now you are into the "must fix AC" season so you won't find deals. I stockpile when I see a good price, but most people don't have storage space and/or live paycheck-paycheck. R4's were used on Chevy's, so no worries about sourcing, but the ports do vary a bit. I prefer one w/ O-ring grooves.

mbolton1990 · #5 04-03-2017, 04:03 PM

They're fairly easy to rebuild and the rebuild kits are cheap, couple vids on Youtube cover it well. Might be a good option for you if you're the DIY type