<firstname.lastname@example.org> wrote in message
> I just took my new-to-me '94 Explorer on its first backroad trip. It
> did GREAT! Gravel roads, fording a foot-deep stream, a steep, muddy,
> rutted road- it handled it all. This is just what I wanted.
> However, I noticed that on long downhills the temp indicator dropped to
> cold. I had noticed that the temperature gauge normally read low, the
> needle right at the line between "cold" and "normal" but figured that
> could be typical.
> I've seen this on other vehicles, and wanted to get it fixed before it
> gets cold and I need the defroster/heater.
> I figured it was stuck open, but when I got it out (good thing I had a
> wobbly adapter and various extensions!) I found it closed.
> So I put it in a pan with the new thermostat, fired up the burner, and
> watched. The old thermostat opened sooner than the new one, and once
> they were opened, I turned off the heat and started adding cold water
> to the pan. The new thermostat promptly closed, but not the old one. I
> removed them from the pan and the old one was still open slightly,
> though it was cool enough to touch the brass part that contains the wax
> I don't know what goes wrong- if the spring weakens or what, but the
> new thermostat works great. There's only two needle widths difference
> on the temp gauge between going up a long hill and going down it, and
> it reads well into the normal range instead of at the bottom end.
The temp gauge on my '92 was reading low so I took out the thermostat, put
it in a pan along with a new one, and the new one opened sooner (around 185
degrees) so I put the old one back in and put the new one on the shelf. It
still reads a little on the low side but better than overheating ;-)
The old Explorers go through a lot of thermostats and it doesn't seem to
matter what brand it is.