I have a 1993 190E 2.3L and have very litte heat in the cold winter
months. I recently have changed the heater valve, the auxiliary water
pump, the thermostat, all to no avail. The engine temperature reads
80C or above all the time even at highway speeds and on cold days. One
thing I did notice is that with the engine temperate at 85 C for an
hour or so the heat gets a little better in the cabin. This makes me
think its a plugged heater core, which I have repeatedly back and
forward flushed. A couple of years ago the flushing of the heater core
seemed to make a difference, now it doesn't.
Any ideas. Is it the climate control system?
The heat is controlled by mixing hot and cold air through some
airflaps. I know the manual heat system is cable controlled, and I
think the climate controlled version operates through vacuum actuators.
If heater valve and heater core is OK, the hot air should also be OK.
But if it isn't mixed in correctly, you will never get any use of the
This could be a path worth tracing.
No, I say it may be the airflap actuators.
It could of course also be the climate control unit, which does not
tell the airflaps to provide hot air. If so, the most probable reason
is, that the thermo sensor tells it is warm enough, or that the unit
does not work at all.
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