I was wondering since my r4 compressor on my 300sd is noisy and going to die. Did mercedes modify this compressor or would a GM r4 be the same, as I have several of those? If it was modified what was done?

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87 300SDL 220K
85 300SD 218K
82 diesel Chevette 440K
85 subaru 4WD turbo
83 4.1L buick powered cutlass THE TOY

I'm not sure about this, but I think if you have a good R4 that fits and has the correct o-ring seal for use with the ridiculous manifold that is used to seal against the compressor, I can't imagine why not to use it.

One thing that I am curious about is that the one bolt that holds the manifold in place against the o-ring seals is a metric bolt. I don't know if this was done for Benz or what. If your compressor fits otherwise and takes an English bolt, be sure to use the bolt from the compressors application, not the metric one from the compressor that you remove, I would just investigate and be careful. If you strip this hole in the compressor, you will have problems and possibly have to toss the compressor.

Good luck,

I second and totally agree with Larry's suggestions. An R4 compressor should be an R4 compressor and "should" be a bolt-on swap (Fed. law required that a certain % of cars imported into US had certain accessories installed in the US - AC systems were one such accessory, so you probably have a US made/installed AC system). Look both compressors over very carefully (bolts/fasteners and how they fit, AC line fit, mounting holes line up, elec connections actually connect, clearances, etc.) BEFORE installing the replacement - not a good idea to be installing the replacement only to find something won't fit.

Good Luck!
Tom

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America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

This is neat. I just want to share this information I found about R4 compressors at some Australian website (I forgot the name of the website) that sold all kinds of compressors:

V3008 New Compressor: GM/Harrison/AC-Delco R4 with Metric Mount Threads, 12 Volt with Coil at 12 O’clock, with 4.97” Single A Groove Clutch, Gauge Line 1.132”, with Plugged switch port for High Pressure Switch. Supplied with Sealing Washers.

GM / Opel / Vauxhall / Harrison / Delco
Part Number: 1134320

GM/Harrison/AC-Delco R4 Compressors do not have an oil sump and therefore, are very prone to failure, if the system is not one hundred per cent. Please make sure when changing R4 Compressors, that you follow our “Compressor Instructions and Warranty” to the letter. We advise that you never fit a rebuilt R4 Compressor, as they are very difficult to rebuild and from our experience, we have not found anyone who can successfully rebuild a R4 Compressor, to an acceptable standard. Our V3008 is a new Harrison R4, not rebuilt.

Replaces: All GM Standard R4 Compressors with 4.93" Single A Groove Clutch with or without Switch port (for use with Super Heat Switch applications please see our technical bulletin number 1002). Will fit Mercedes, Rover SDI, Land Rover, etc.

Replaces GM part numbers: 1131198, 1131200, 1131340 & 1131382.

Hey ZBenz, I just replaced my compressor. Email me if interested in the details. I love my 85 300Sd.

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Orland Park, IL
1985 300SD 215,000 miles

I have about 8 compressors from various cars over the years... and would like to test them..

Anyone know what a bench test setup should include ?

Thanks, Greg