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#1
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2000 C280 A/C not cooling - compressor?
2000 C280. No cooling effect. Pushbutton Module diagnostics shows compressor discharge pressure (#07) of 6.6 bar and temps around ambient on #03 (heater core) and #05 (evap temp).
I put my gauges on the system and I get a high side pressure of around 8 bar at idle rpm and at 3000 rpm. On the low side I get about 6.8 bar at idle and when I raise the engine rpm to 3000 the low side pressure drops slowly to around 4.5 bar. Also, the low side pressure randomly bounces around a bit. Both the suction lines and the compressor discharge piping is at ambient temp. I suspect the compressor is the problem. Can anyone conform or suggest further tests? |
#2
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Either a bad expansion valve OR compressor.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES) ASE Master Technician Mercedes Benz Star Technician (2 times) 44 years foreign automotive repair 27 Years M.B. Shop foreman (dealer) MB technical information Specialist (15 years) 190E 2.3 16V ITS SCCA race car (sold) 1986 190E 2.3 16V 2.5 (sold) Retired Moderator |
#3
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Follow up. It was the expansion valve. Thanks mbdoc!
I do have one concern after opening the system. There was a black residue on the high side ports of the expansion valve. The low side ports were clean. Could this be a sign that the compressor is headed for failure. IIRC, in the past Denso compressors (and the Ford versions) had a characteristic called "black death" before failure. |
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