@Rednucleus is there a way to check that sensor, or do I just buy another one and plug it in and see if I get a different result?

 

I think as someone previously suggested, you need to verify that the temperature is actually over 200°.

 

Checking it with a meat thermometer in 2 locations- stuck in between the radiotor fins below the upper radiator hose, and immersed in the coolant after unscrewing the radiator cap- it's at 145 degrees after running and the dash gauge reading 240. This is without the thermostat installed.

So possibly the gauge in the cab is not working correctly? I know a meat themometer is not the most scientific, but I've read on other forums that it at least ballparks it.

 

It sounds like the temperature sensor is bad or the gauge is.

 

You need a tstat installed as it restricts the coolant flow as to allow it to dissipate the heat (keeps coolant in the radiator longer) else You're just circulating high temp coolant through out the system.

 

[QUOTE=73shark;480089]It sounds like the temperature sensor is bad or the gauge is.[/QUOTE

The temp sensor is brand new. I know that doesn’t necessarily mean it’s good, but…

Is the temp sensor the one on the side of the block, or at the top?

 

Thanks. I removed the thermostat at the suggestion of another forum member to determine whether it was causing the overheating issue.

 

[QUOTE=Mark_Cool;480091]I don't know which one is for the gauge and which one is for the computer.
The purpose of the thermostat is to keep the engine coolant at the proper operating temperature which on most modern vehicles is around 200°. A normal cooling system without any problems and with the thermostat removed, will never allow the engine to get to the operating temperature under normal operating conditions.

 

The one on top is the computer, the one down low on the side is your gauge - unplug it you should see a change in the gauge to verify. In my 93 if I unplug the top one my motor dies.

 

Aftermarket parts store sensors are not reliable. Use GM sensors only.