Hi. I'm new to the forum and Mercedes diesel ownership. I recently purchased a 1982 300D Turbo that is in rather nice condition with no rust or body damage. The engine starts and runs well. The transmission shifts great if I "drive it like I stole it". But my main concern right now is the ACC. I drive with the ACC button set on "Economy" mode. In this mode I'm assuming that the AC compressor is working at an unstressed state. The problem is that when I put the ACC in either normal setting something under the hood, to my best guess, freezes up and stalls the engine. I've done a search and haven't been able find anyone else having this problem. Am I blessed? Any suggestions would be appreciated. I have most of the other problems with the car, tach, speedo, seats, slipping trans (unless driving with my foot to the floor) and too much engine vibration throughout the car when idling. The forum is great and I'll be getting to these repairs as time allows, but since this is my wife's car, I want to get the AC, trans and speedo ( for oil changes, etc.) working properly as quickly as possible. I'm open to the wisdom of the forum. Thanks for all your anticipated suggestions. I'm sure I'll become one of the regulars...

In the economy mode, the AC compressor is not operating. In the other modes it is. I suspect that the compressor is frozen or has some other problem inhibiting it from turning.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Thanks, Kerry. I guess I'll have to get an owner's manual for the car to save needless posts. My guess would be the compressor. Where might I purchase an AC compressor? Is there a good source for rebuilt units? Would you advise converting to R13 in the process? Any other parts of the AC system that might be worth replacing while I'm at it? Lots of questions, thanks for the response. I'll be doing the work myself so am more concerned with the price of parts than that of labor. I've got a terrific mechanic who is willing to help as necessary, i.e. evacuating the AC and refilling with R13 if recommended. He works on domestic iron and doesn't have any interest in the Mercedes, particularily this vintage. Thanks again...

Dan

I know very little about the AC system. However, I recently looked at an early 80's Td. The records were meticulous. The first compressor lasted a long time (12 years or so). After that, it showed the compressor being replaced on a regular basis, almost every year. That makes me suspect there are serious problems with replacement compressors.
I'd be inclined to stick with R-12 myself. I put R-134a in a Buick I used to own and the higher pressures were hell on the belt. It couldn't carry the load and squealed most of the time.
If you want to be adventurous, replace it with propane.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Do a search on here - there has been much discussion concerning the ACC on these cars. Sounds like you need a new compressor. They can be purchased new from about any auto parts house - Advance, Autozone, etc... They are relatively cheap. Stick with the r12. What I would suggest - take it to a reputable a/c shop, have them vacuum and suck out the system. Take it home and replace the dryer/compressor then return to have the system lubed up and charged. Get the oil filling instructions for the compressor prior to installing it and make sure you follow them.

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Jim