Coolant Temp Very High...

[David N]

Or so my AE says it is. The truck runs fine. But my AE is saying my coolant temperature is over 300*. The dummy gauge in the dash is right where it normally is, and no lights either. Engine oil temp is around 200ish.

And also, I just checked it again, and after the truck sat for 16 hours, AE is saying the coolant temp is 220*. So obviously, something somewhere is wrong. But where do I start? The sensor is fairly new, but I will change it if need be.

Ive read there is only one coolant sensor, but is there another I don't know about?

 

[ToMang07]

I can't remember where the point is, but once the coolant gets up to that temp...the readings in AE goes nuts. Not sure if it's a AE issue or sensor issue, mine does it too...no idea why. My temps are fine.

 

[David N]

Its so weird.

Also, when I read Fuel Pulse width, it says its only .33-.4 Very strange. Im starting to wonder if AE is somehow messed up?

 

[ToMang07]

Its so weird.

Also, when I read Fuel Pulse width, it says its only .33-.4 Very strange. Im starting to wonder if AE is somehow messed up?

My guess would be that it's more related to the older technology/computers in these trucks.... hopefully somebody who actually knows can step in and clear things up.

 

[Ron's Power Stroke]

the PCM does not read coolent temps.....there for AE can not read it as well..it uses the oil temp....the water temp sensor only tells the gauge on the dash what temps are and it still isnt right on...

 

[Arisley]

The gauge on the dash is really just an idiot light with a needle. As long as the temp stays within a certain range, the needle does not move. If it goes out of that range the needle starts going up, fast.

AE does not do coolant temp very well at all. There is something wrong with the pulse width though.

 

[Lethalthreat7.3]

The temperature sensor is a thermistor that changes the resistance reading according to engine coolant temperature. The gauge reacts to the varying resistance indicating cold to hot. Diagnostics are to know the coolant temp sensor resistance correlated to the actual coolant temperature. To test your gauge use a potentiometer and change(within the sensor parameters), resistance while watching the dash gauge. It sound change as you turn the dial.

 

[Arisley]

Correct, however, there is a big range right around normal where the resistance does not change at all. Therefore the gauge stays rock solid. If it was mechanical, you could set there and watch the temp gauge rise up when the thermostat closes and then fall off every time the thermostat opens up.