If it 'overheats' with it shut then unless the ambient temperatures are very
high there is something wrong - either the engine is producing too much
waste heat (e.g. over advanced or retarded timing) or the cooling system
isn't getting rid of it as it should (e.g. blocked radiator). But then true
overheating is when you get coolant loss or steaming from the radiator cap,
not just the temp gauge needle going above 'normal'. If it gets to the H or
right round to the highest number then it is certainly a warning to make
sure everything is OK, but true overheating can cause it to get much higher
than that. With a mechanical fan it is normal for the needle to rise above
the normal position (on a cool day) in very warm conditions, or slogging up
a long hill, and indeed it is normal for electric cooling fans to cause the
needle to get to about mid-way between N and H before the fans cut in
anyway. Having said that using the heater is a useful way of getting a bit
more cooling under extreme conditions.
PaulH.
----- Original Message -----
> Sorry guys... Water control valve on the back of the head. From the answer
I have receieved it turns the heat off. However.. mine was bypassed and
completly shut. I opened it and now my car doesn't over heat:-)
|