f-32 with chrysler 318 water temp problem

[Macdiver]

My F-32, with Chrysler 318 have a water temp problem. Guage stuck at low temp then went to 240 and stayed there. changed thermostat but problem persists. There are two sensors wires in front and below the water tank, when the lower one is disconnected the temperature guage goes back to normal but the temperature does not rise on the guage. Has anyone had a problem like this??? Looking for a solution from anyone. Thanks, Macdiver

[prowlersfish]

What is the temp reading on cold start ? when you disconnect the one sensor and the gauge goes back to normal what are you calling normal ? Do you have upper and lower helms ? if so are both doing the same ?

[oldboat1]

Actual engine temps OK, though? A pyrometer is a good tool to have onboard -- check manifolds at various points, looking for blockages/hotspots. Raw water and perhaps circulating pumps due for service?