I OWN A 1982 300D TURBODIESEL WITH A 134a SYSTEM. I RECENTLY REPLACED THE COMPRESSOR AND RECIEVER/DRYER. AFTER EVACUATING AND CHARGING THE SYSTEM I STILL GET WARM AIR. THERE AR NO LEAKS AND THERE IS A NEW PUSHBUTTON UNIT ALSO. MARITAL HARMONY IS RIDING ON ANY RESPONSE. THANKS

Is the compressor clutch engaging? If so, what are the high and low side pressures when the compressor is operating?

THANKS FOR ANSWERING, YES THE COMPRESSOR IS ENGAGING. THE LOW SIDE WITH ABOUT 33 OZS OF 134a IS 80 LBS, AND HIGH SIDE IS THE SAME THE ORIGINAL COMPRESSOR(FACTORY) WAS REPLACED BECAUSE IT AS WORN. I INSTALLED A SECOND ONE THAT WAS DEFECTIVE OUT OF THE BOX AND SIEZED DURING INITIAL CHARGING (YES I OILED IT FIRST AND SPUN IT BY HAND PRIOR TO INSTALLATION). ONE THING I DID NOTICE DURING THE MOST RECENT CHARGE ATTEMPT WAS THAT IT DIDN'T TAKE 134 AS FAST AS MY OTHER CARS EVEN ALLOWING FOR DIFFERENCES IN SYSTEMS.

THANKS AGAIN IN ADVANCE, KEVIN.

Were these pressures obtained with the compressor on? What you've quoted is representative of an equilibrated system with the compressor off.

Several factors come into play (ambient temperature, freon charge level, oil charge level, engine RPM, etc.) but with a R134a charge and a functioning compressor you should see low side pressures below 50 psi and high side pressures over 300 psi.

Sure am glad I'm not selling you compressors.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

You need some pro help. I would ask for help on this. I think your procedures for oil introduction or charging may not be proper.

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Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM