mercedes or GM ac compressor

Hi, My 1984 300SD needs a new ac compressor. My last mechanic said mercedes compressors were junk and GM's were better. I'm running R12 in the AC. I've read in past posts that Mercedes ones are better because
they are oriented correctly.
Any opinions?
Also, what is the correct amount of oil and freon for this car?
Thanks, Jeff
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I buy my compressor on ebay... save a ton of money.
Here is one... brand new... not rebuilt for $180 shipped.
http://cgi.ebay.com/ebaymotors/77-93-Mercedes-Benz-190-240-300-Series-AC-Compressor_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1171Q7c66Q3a4Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a0Q7c293Q3a1Q7c294Q3a200QQ_trksidZp3286Q2ec0Q2em14QQhashZitem3a4e20d9d9QQitemZ250418878937QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
Mercedes R4 is the same Delco R4 used in GM... there is no difference between the two. The only thing might be different is the clutch and the wiring but it does not seems for strictly for the R4.
For the other Nippondenso, the difference is the wiring harness which some mechanic spliced it to make it fit... and the clutch is definitely different.
I usually buy from the guy who has red picture but he doesn't have R4...
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Tiger, Thanks a million for the link to ebay. The other place I found was techchoiceparts. They had a new compressor for 180.
Thanks again and everyone stay cool this summer.
Jeff
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Tiger, Who's the guy with the red picture?
Jeff
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Don't just buy any compressor just because it is new. I bought one that was new, but not a AC Delco and it didn't last very long and was nothing but trouble. I just had a new compressor, AC-Delco, put on and I paid the AC shop in Las Vegas $430 for the part. I looked around on-line for one but I couldn't find an AC Delco one new.
That's the make of compressor that was on my car when I bought it. I don't know if it had been replaced or not, but I doubt it because the car was mostly used in Seattle, where you don't use AC much.
I have driven though Death Valley and this week to Venice Beach and back and the new AC setup has worked just like when the car was new. I had them put R-12 (freon) in because that is the coolant the system was designed to use. We tried 134a once, but it didn't cool well enough. I replaced the evaporator and condenser last season.
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http://cgi.ebay.com/ebaymotors/85-93-Mercedes-190E-260E-300E-A-C-COMPRESSOR-NEW-KIT_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1171Q7c66Q3a4Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a200QQ_trksidZp3286Q2ec0Q2em14QQhashZitem3351389afeQQitemZ220405996286QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
He has red pictures... on ebay that is. I bought two compressors from him.
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The Mercedes compressor is bottom mounted. There is a passage that allows oil to get into the bearings. The proper orientation is marked with an X. The Delcos are apparently usually top mounted so that when used on the Mercedes, the compressor is upside down and oil won't flow into bearings under gravity.
Many have used GM compressors on MBs with good results - presumably enough oil splashes around to lubricate the bearings but perhaps the compressor life may be affected.
Here is an old post on the subject by the late Dr. Marshall Booth (an MB diesel expert!):
http://www.mail-archive.com/ snipped-for-privacy@okiebenz.com/msg57091.html
CN
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Carnut... thank you for your information. That is critical information and may be the only reason why some of those R4 don't last long.
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