On Jan 26, 2:13=A0pm, "John" <j...@[EMAIL PROTECTED]
> wrote:
> Here's the situation, looking for confirmation on my possible diagnosis
or=
a
> point in another direction.
>
> 1989 900 T
> Engine up to temperature and idling in a parking lot with the outside
> temperature around 20 degrees F. =A0The temperature gauge starts
climbing =
and
> at the same time the cabin heat starts blowing cold air. =A0Once we
start
> driving again the heat comes back and the temp gauge goes back to
normal.
>
> Are we talking a bad thermostat here or am I way off base?
The cabin heater matrix has a thermostatic valve in. When the
temperature comes back down (while driving) it is allowed back into
the cabin.
Does the temperature rise up to an indicated red on the gauge? Is the
radiator fan working? Check this by baring back the terminals on the
radiator thermostatic switch and bridging the terminals with something
metal (insulating yourself from the voltage, of course). Does it come
on at about 2/3 - 3/4 up the gauge? Check the fuse.
One final things - there is a small hose that runs from the top of the
radiator to the coolant expansion tank - feel it. Is it cold? If so,
it's blocked ... most likely at the expansion tank end spigot. That
may cause an airlock where the radiator thermostatic switch is, so the
radiator will not work ... overheating.
You can change the thermostat - go for an 89 degree one. Might as well
anyway for what they cost - check out the things above and re****t
back. We should be able to get this one sorted between us.
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