Spoke with a co-worker yesterday about his '79 Euro-spec W107. It has
A/C,
but manual climate controls. He says his driver side heat is always
on,
which I thought was a standard default for a failed mono-valve, but I
don't
know if the manuals come with those.
If this '79 is like our US-issue '76, the manual system has a
vacuum-controlled water valve. When either heat lever is lifted
off of MIN, a vacuum bleed valve is opened up resulting in the
water valve actuator being released, letting hot water go through
(both sides) of the heater core. Air blend flaps are then used to
modulate the temperatures on both sides.
The local indie quoted him ~$600 to
fix the problem, which seems to be a bit ridiculous if it's just a
mono-valve. Any thoughts?
I'd likely charge more, if the problem requires new vacuum valves
or anything like that, because the console has to come out. (Which
requires the seats to come out first, etc.)
With luck it's just a broken water valve dingus, which is trivial
to replace under the hood. Oh, and the adjustment levers have
tightening screws on their pivots, IIRC, if they come loose the
lever moves without moving the air blend flaps, and I suppose the
vacuum valve too. That's just a nut to tighten, it may be that
this can be done from the front with the console in place. (You'll
have to remove the HVAC face panel, of course.)
-- Jim
