I have been working on this 1987 Mercedes diesel wagon for a guy. It came to me with the A/C not working and the compressor front seal leaking profusely.

HERE IS WHAT I DID: I pulled the compressor and sent it out to a reputable place in Florida for a reseal and rebuild. It uses a small rotary type. I replaced the CONDENSOR, RECEIVER DRIER, EXPANSION VALVE. I blew out all of the lines.
I added the recommended amount of refrigerant oil. I evacuated down the system for 30 minutes. I charged the system and fired it up.

PROBLEM: I am running too high on the high side (275psi to 300psi) and too low on the low side (10 psi at idle and down to 0 at rpm)

I am running Duracool refrigerant (replaces R12). Ideal pressures with Duracool should be 24-28psi on the low side and 175psi on the high.

To say the least...... This car really has me frustrated!!! I have had it for 3 months doing a bunch of stuff to it. I want to see this thing go BYE-BYE!!!!!BIG TIME!!!!

ANY AND ALL HELP MUCH APPRECIATED!!
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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

Gotta be some kind of restriction. If you pull out the expansion valve, and disconnect the fitting at the compressor, you should be able to blow air freely through the system without resistance. You might have blown some crap loose and it might have clogged the new expansion valve or the drier.

Bill

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Bill

Backyard Shadetree Mechanic, 30 years running.

1987 300TD
1988 300E (sold, sniff)
1999 S320
1981 Volkswagen Rabbit Truck (Diesel)
2001 Ford Expedition
1988 Suzuki Samurai
On my list to buy: R129, for me, and a R107 for my wife.

Thanks, I am going to order another expansion valve.

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.