Searched the archives on this without much luck....

In late May and early June we made a 4000+ vacation from Washington State,
through So. Cal, Arizona, Utah and Idaho with nary a problem in our recently
acquired '87 Westphalia.  Last weekend we took a 120 mile trip to go camping
and wouldn't you know it......

On the way back the engine coolant warning light began flashing after
driving about 30 miles on the freeway.  The temperature gauge needle was
just below the light.  We stopped and checked the coolant level in the
expansion tank and the refill tank and both were OK.  Belts looked fine.
The owners manual said that the fan should be running when the light is on,
which it wasn't.  Checked the fuse (it couldn't be THAT easy) and it was
fine.  Engine temp didn't seem to be extreme.   We let it sit for 10-15
minutes and started again.  Keeping the speed to around 55 mph we were able
to go 20 or so miles before the light came on again.  It doesn't go on
around town or on short runs on the freeway.

I have not worked on any of my vehicles since selling my '67 bus 12 years
ago and have lost what little mechanical apptitude I had.  I am hoping that
this might be something simple to correct that I can do myself.  My guess is
that the fan motor has gone out.  My second guess, after looking at my
Bentley is that it might be the thermo-switch for the fan.   I am guessing
this is similar to a thermostat on a "normal" car and it looks like
something I can replace myself.  How's that for creative diagnostic
thinking?)

Any suggestions or guidance would be appreciated.  Thanks in advance.

Kevin Ainslie
Puyallup, WA
'87 Westphalia-Gonzo

It isn't pollution that's harming the environment. It's the impurities in
our air and water that are doing it. -Dan Quayle