Hi, can anyone comment on this problem:

BMW 1987 535i

Problem: Cabin heater starts to blow cooler air when car is moving.
a.. Heater starts to work well when vehicle is not moving.
b.. Radiator, thermostat, waterpump, hoses are all brand new. All working properly.
c.. Pressure test shows no leaks in cooling system.
d.. Coolant remains at constant level with virtually no sign of being depleted.
e.. No blockage exists in heater core.
f.. Engine running very strong with no sign of malfunction.
I've been told by a mechanic that the problem is most likely a head gasket leak.
Does this sound reasonable given the above observations?

Thanks for any feedback you may provide.

Grant

Grant wrote:

First - find a new mechanic. He wants to do a $2,000 job to fix a $15
problem.

There is an electrical control valve for the heater water - and yours
has failed with the classic failure mode. There is a kit to fix it
available from BMW (about $15 - the valve is about $50). It takes about
10 minutes to install, and if you're handy you don't even have to drain
the coolant (the valve is up high).

I'd suggest investing $50 in the Bentley E28 manual and firing your
mechanic. It will be the best $50 you'll ever spend on the car - even if
you do NO work on your own - you'll be able to tell the bonehead you're
using how to fix things.

Much appreciated Don

I will purchase the manual you suggest and look forward to reading through
it.
Also, the mechanic will be given the proverbial boot.

Thanks for your feedback,

Grant

"Don" <admin (AT) 192 (DOT) 168.0.2> wrote

In article <S%1md.34$Pe3.29091 (AT) news20 (DOT) bellglobal.com>,
Grant <gkimmons (AT) hotmail (DOT) com> wrote:
Ask him how a 'head gasket leak' can cool the temperature of the water
circulating in the heater. I'd love to hear the answer.

--
*I don't suffer from insanity -- I'm a carrier

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.

1) Fred has offered some good advice; however, you don't mention
the fan clutch. BMWs (and many other cars) have a viscous clutch
on the fan that responds to temperature: if things get hot, the clutch
couples the fan to the drive belt to increase airflow/cooling. It may
have failed and is driving the fan continuously, which would cause
the problem you're seeing.

2) get another mechanic.

3) please post in plain text, not HTML.

Floyd

Thanks for the additional comments. I'll take note of your suggestions.

Grant


"fbloogyudsr" <fbloogyudsr (AT) nwlink (DOT) com> wrote

In article <10php8nlsr9tb11 (AT) corp (DOT) supernews.com>,
fbloogyudsr <fbloogyudsr (AT) nwlink (DOT) com> wrote:
I'm not quite sure how the radiator cooling fan can effect heater
temperature? The heater will work with the rad still cold - that's the
function of the thermostat.

--
*When the chips are down, the buffalo is empty.

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.