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.
Last edited by Bill Hanlon; 02/20/2024 2:32 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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