Heat works, but engine temp stays cold

[jco77on]

When I bought the truck, the temp gauge was reading quite cold (but not sitting on cold) and the heat didn't work. I drained the coolant and it was very brown. Installed a new thermostat, refilled the coolant, and burped the system.

Now the heat is working excellent, but the temp gauge says full cold (doesn't move at all that I can tell). Put a ground on the temp gauge wire and the gauge went to hot, so that's good. Installed a new coolant temp sender, but the temp gauge still doesn't move from cold.

Ideas?

Oh, also the fan that was on it was the OE plastic garbage so I put a new aluminum fan in it. That thing moves a heck of a lot of air. Wondering, is it possible that my fan clutch is bad and the fan is spinning full bore all the time and overcooling the engine?

 

[Lariat]

Sounds like the sensor is shot. Replace it.

 

[bulrid8]

When you put in New sensor you didn't use Teflon tape, did you? The sensor has to ground through the threads.

 

[jco77on]

I didn't, but there was some already on it. There was some on the stock one that i removed too though. If that's a problem, why do they keep putting tape on the sensors at the factory??

 

[Terry]

Do yourself a big favor and get some aftermarket gauges. My gauges would do all kinds of strange things so I bought some cheap sunpro gauges and I could not be happier. You can watch the thermostat open and close by temp, Oil pressure is direct not from some garbage sensor. The biggest headache was the gas gauge but fixed that is another story.

 

[jco77on]

Determined the sensor is good, pretty sure it's an air bubble in the system. Going to do more thorough system bleed tonight and see if that helps. Jack up the front end, use a funnel at the radiator filler, etc.

 

[Terry]

Determined the sensor is good, pretty sure it's an air bubble in the system. Going to do more thorough system bleed tonight and see if that helps. Jack up the front end, use a funnel at the radiator filler, etc.