Hot Coupe

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

Keith questioned whether his Coupe was overheating.

 You should be able to isolate some of the components by remembering that
the coolant temperature in the block is controlled by the thermostat and
this is the temperature indicated on the gauge. The switch senses the
radiator coolant temperature and turns the fan on.

Watch the temperature gauge as you drive at steady state, cool temperature
and light load between 30 and 50 mph. The temperature should stabilize with
the fan off and this should be the indication of the thermostat opening
temperature. If the temperature is stable and in the normal zone the
thermostat is ok. If the the temperature is stable and near the red line you
either have a second bad thermostat or the sensor is reading hot. If it is
not stable maybe it is a bad pump or collapsed hoses.

Assume the temperature is stable and indicates in the normal range. Go into
an idle with the A/C off and note the fan turn on temperature. If it is in
the red zone, the settings are too high. The fan turn on temperature will be
higher than the thermostat opening temperature or the fan would run all the
time.

If you suspect the gauge find a friend with a digital thermocouple readout
and stick a thermocouple in the coolant (under the hose clamp into the top
tank is best) and compare with the gauge when the coolant is above
thermostat temperature.

Bob Cummings
87 Coupe GT 110k