[W126 Coupe] AC Problem Part 3

[Tom Oelsner]

Dick, Markus et al
Thanks for all your pointers.
Markus, The system was not flushed.  I should point out that there was no
coolant in the system for about a year.   Today while driving, I did a few
things playing with fan speeds, vent controls etc.  Although the outside
temp was only in the low 70s (in my case temps above 70 are reason enough to
run the AC) the AC was putting out really cold air even when barely in the
blue indicator zone on the thumb wheel.

Dick, why would a belt not maintaining tension cause you to think that the
clutch is slipping?  And how does one check for clutch slippage?  I used
Duracool refrigerant.  Fan works at all speeds and air flows freely.
Tom
  -----Original Message-----
  From: mbcoupes-bounces at mbcoupes.com
[mailto:mbcoupes-bounces at mbcoupes.com]On Behalf Of Dick Spellman
  Sent: Tuesday, October 11, 2005 2:10 PM
  To: Mercedes Coupes Mailing Lists
  Subject: Re: [W126 Coupe] AC Problem Part 3


  Hi Tom:

  I would begin to guess that the clutch on the compressor is going
(slipping).  High speed gets just enough turns on the compressor to get cool
air and low speed the slippage is marked by poor cooling.

  I can only base this on your continuing belt trouble which only involves
the pulley and clutch where you repaired the idler pulley previously and the
fact that you say your engine coolant temps are in line with 85-95 (even
110) are all okay.

  Just a guess but, I 'd have that compressor clutch checked and if that's
not it you've got a gremlin in there that goes beyond normal means to
repair.  Last thought, was this R-12, R-134A at 80% or some other
refrigerant???

  One last dumb question, independent of the air movement at 75 MPH does the
ACC fan work at all speeds and does the air flow freely out of the center
vents when AC switched ON??

  Dick
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