Overheating onset

[Huw Powell]

>  I've
> narrowed the problem in my mind to a bad fan thermoswitch or a bad fan
> motor.  Since there was no sound associated with the failure, I'm
> leaning toward the thermoswitch.

Narrowing the problem to certain things implies testing and eliminating
all possible causes...

While the type 44 is more complex than the little cars, some of the same
basic principles apply.

To test the thermoswitch at your radiator, undo the plug and jump the
appropriate terminals in the connector.  This simulates a warm radiator
and should make the fan run.  If it does, the thermoswitch is bad.

If it does not, the switch may still be bad, but something else is
wrong.  See the comments about the fusible link, test the relay(s) that
run the fan, etc.  Someone posted how to make the fan run with the
climate control, if that doesn't work there is probably a wiring or
fusible link or relay issue...

A schematic will be handy to make sure you are testing appropriate
components in appropriate ways, of course.

Your general temp reports are consistent with the fan not running at
all, by the way.  Unless there is a severe load from what I've seen
these cars tend to not need the fan when running down the highway at a
decent speed.

> Just looking for some suggestions regarding a problem that popped up
> Saturday a.m. on my 91TQA.  I was in the Boston suburbs for a wedding.
>  Drove out from Western Mass. Friday, about a  2 hr. drive, with no
> problems.  Then on Saturday, while poking about Chelmsford, the temp
> gauge began rising and set off the chimes and the red display.  Stopped,
> checked coolant level, which was fine, as was fuse #15.  When I headed
> back down I-495 to the hotel, the temp came back to slightly higher than
> usual, and all warnings disappeared.  Sunday, did a little driving
> around, keeping an eye on the temp gauge, which remained volatile, then
> headed back home along 495 and I-90.  At speeds between 80-95 (and
> sometimes even a little slower!), the gauge remained at normal levels.
>  When I got off the Pike at Exit 1, and began driving in town traffic,
> it began climbing again.  While driving at steady 40 or so, the temp was
> no problem.  When stop & go began, the gauge climbed again.

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/