Originally Posted by Bill Hanlon
The mounting point of the mechanical temp sensor in my GMC is in the head between cylinders 5 and 6 which I've been told is the hottest area on the head, while the thermostat is off the front end of the head where I have an electrical temp sensor (see Segal's Law) mounted in the thermostat housing. It is not unusual to see a 10 to 20 degree difference between the front and back (the back being hotter) during conditions that cause a change in operating conditions of my truck (long hills up or down, initial start up, even slowing down for a turn after a few miles at steady highway speeds).

Or it may just need burping like you said.

I only use the temperature probe at the thermostat housing. So that is actually the temperature changing.
It would be interesting to run another thermometer to the head but where would I mount it?

1953 Chevy 153A 3/4-ton
Working on my project since 2015
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