I have a 97' F150 4.6 V8. No matter how long I drive, my temperature gauge will not reach the "operating range". The heater works great. I replaced the thermostat this weekend and that did not help. I'm thinking it might be the temperatue sensor, if so, where would I find it.

Thanks

 

How far away from operating temp is it? That is actually a GOOD thing as long as you've got heat, unless it's way off. More info!

 

That's not even close to a good thing. If it never reaches operating temp, it never goes into closed loop so it stays in warm up mode all the time. That means your power and your mileage sucks.

What part about that is good?

 

The gauge only goes from 0 to the just below the bottom line of the operating range.

 

No...The engine reaches closed loop when the Oxygen sensor produces a rich signal, the ECT (Temp sensor) Reaches a set value that is agreeable with the MAP/MAF, And the time conditions have been met. If none of these are checking out, the MIL lamp will be illuminated. He has no check engine light, the vehicle also has good heat. Your saying it's better to run hotter than run cooler? Too cold is unaceptable, but read the facts.

 

The check engine light is on, sorry I didnt mention it before. I didnt think it would have anything to do with this problem. When I had the code read, it said "cam shaft sensor". I have replaced that and the cel is still on, and still reads "cam shaft sensor.

 

Cam shaft position sensor won't have anyhting to do with the engine temperature, correct. The cam sensor is used to tell the PCM where the camshaft is located in relation to #1 Cylinder. It's generaly used In Sequential fuel injection, because Instead of timing the injector to the ignition, they time it to the intake valve. As for the original problem; How cold is this thing running?

 

What degree thermostat did you put in? How quickly does the guage reach the temperature it runs at? Is the temperature the guage stabilizes at(runs when it gets fully warmed up) just below the normal line?

 

I think it's better to run on the warmer side than the cooler side. Helps minimize sludge buildup and all. The cooling systems in these trucks are pretty good nowadays, so biasing towards warm over cool or cold isn't really a bad thing.

Maybe the thermostat the OP bought is defective or something. Does the upper hose ever get hot to the touch?