Wild Temp Gauge

["R. Cummings" <cumm@flash.net>]

My 87 Coupe GT suffers from the digital dash going blank once in a while and
when it comes back on the elapsed timer has zeroed. So far I can live with
that. Yesterday was the first cool day we have had since June and a new
glitch has developed. The temp gauge suddenly goes full scale and the
warning light comes on. Just as suddenly, it drops backs to normal. These
movements happen in the blink of an eye. The coolant level is fine. No
coolant appears to be leaking and none has been added in maybe a year. There
is no evidence of overheating.

I assume I have problems with the sender or the gauge. The easiest to check
(but maybe the least likely culprit ) is the sender.

I'm going to take a look at the water pump and timing belt this weekend. A
failed water pump resulted in a bunch of bent valves about 30,000 miles ago.
 
Can someone tell me where the temp sensor is on the engine? Any BTDT's
appreciated.

Bob Cummings  87 Coupe GT 120,000 miles