Hello.

Okay so this started yesterday night.  My wife and I were on vacation
and had our 2001 Explorer parked over at a friend's house after being
dropped off at the airport.  We came back and it was covered with
sawdust (my friend had been doing a little wood cutting).

So, we get in and drive home.  About 1/4 home I notice that the temp
gauge warning light comes on and the gauge itself it just about over as
far as it can go.  Now, I'm just about to look for a place to pull over
when the thing starts dropping back down to the middle range.

Okay, that was weird.  It stayed there the rest of the way home (about
another 30 minutes or so).  So, this morning I get up to drive to work
and about 4 miles from home it begins it's climb again.  This time I'm
watching it pretty carefully, of course.  It hits the same point and
after staying there about a minute, drops back down to the middle and
stays there for the rest of the trip to work.

It does climb a little when stopped at a light or something, so I'm
guessing the wind from driving on the highway is cooling it a bit.

So, my question is:  Why does it climb to the high point in the first
place?

Sawdust?  I'm guessing that's most likely the case and will clean it
when I get home, but could the temp sensor?

Any ideas suggestions are greatly appreciated.

Thank you.