Subtitle: When you're hot, you're hot.  When you're not, you're not!

My 84 Vanagon just developed an irritating syndrome.  While driving
normally with no traffic, the temp guage suddenly shot up from the normal
mid-point to the top of the scale.  Coolant level is fine, no observable
leaks, engine behavior normal.  Just to be safe, I shut it off for 2 hours.
(Ambient temp is 70 F)  Upon restart, the guage immediately indicated hot
at the top of  the scale.  Ever vigilant, I turn on front and rear heaters
to max and drive cautiously.  The guage returns to normal in a few blocks.
Two miles later, the guage again shoots up to hot, stays there for a few
blocks, and then quickly returns to normal.

What is going on here?  Do I have a bad gauge, a poor ground, or ?  Could
the readings be accurate, even though they fluctuate so rapidly with no
apparent physical cause?  Should I continue to drive, while keeping a
careful eye on the coolant level, waiting to observe a pattern of symtoms?

Any thoughts/suggestions will be greatly appreciated.

Budd Premack
86 Syncro, 84 Vanagon, 73 Super
Minneapolis, MN
bpremack@wavetech.net