I have a 1992 Dodge Ram 350 pickup, I'm having problems with the engine temperature. The temp gauge will read extremly hot then when i stop it will read very cool after the truck has been running for a while and i know its not that cold. I have replaced the thermostat and it sounds like the sensor to me but i can find it. Can anyone help me and tell me where the coolant sensor is located?

 

it is on the driver side of the back of the head its sort of set in the back of the head

 

Yep 94 cummins got it! I would check your body ground from teh battery to teh radiator core support, when they go bad the gauges seem to run funny. Try running a heavy gauge wire from the negative on the battery to the core support and one to the block, also run one from teh block to the firewall or frame. Teh ground wires are kinda small on these trucks and give you all sorts of crazy problems.

 

yours is a little different cuz i've got a chevy sensor in mine, but should be in the same spot. The rear most valve cover is on the top of the pic, its back and down from it.

 

that would be it. Fu#er is a pain to get out with the head still on the trcuk. its 3/4" pipe threads