Gene K

I had my truck on engineering mode the other day and noticed that wile my trans generally was 89-90C once fully warmed my Engine Coolant Temp varied from 90C - 101C (Lower after a long period of closed throttle and higher with sustained climb or acceleration) and generally 96-98C at steady speed.

Does anyone know if that is inferred coolant temp or actual cylinder head temp despite what's on the screen?

I would have thought the trans temp would track with engine temp at least after sustained cruising with the liquid-to-liquid cooler. A roughly 15F discrepancy is odd.
​
'18 3.5EB

Crazy Canuk

Gene,

I have the same issue:

https://www.f150forum.com/f118/calli...473306/index4/

52merc

From what I've read, it seems that what you are seeing is the inferred engine coolant temperature as provided by the GWM over the HS-CAN3 bus, and not the actual cylinder head temperature sensor output which is hard-wired to the PWM and then processed and sent to the GWM via the HS-CAN1 bus.

Gene K

If it's inferred and in the ball park I would expect the trans and engine temps to track together during a continuous cruise with the thermostats open. I would think a 98C Coolant temp would warm the trans to the same temp.

Could be placement I guess but 7-9C (11-14F) typically is more than I would have expected.

52merc

The transmission fluid is first cooled by a coil in the return tank of the radiator, and if equipped and needed, cooled by an auxiliary cooler mounted in front of the radiator. Although engine temperature may increase, increasing the coolant temperature entering the inlet header, if the radiator is providing sufficient cooling, the return tank temperature should not vary or vary nearly as much as the engine temperature. The transmission cooler circuit has a thermostat valve which controls how transmission fluid circulates through the circuit. Therefore, the transmission fluid temperature will not always track the inferred engine coolant temperature.

Gene K

Doesn't work that way on the 18+ with the 10R80.
They have one large Liquid-to-Liquid Cooler (sourced from the SuperDuty) back at the trans. Coolant is sent from the radiator to the cooler. No trans fluid goes to the radiator and no auxillary air-to-liquid cooler except on the Raptor.

52merc

Sorry, forgot you had the 10-speed, but part of what I said is true. The return side of the radiator is used for cooling and there is a thermostatic valve, so it is still not going to track CHT or ECT.

Phillbo

How are you guys monitoring these temps?

GerdBBeckmann

Hello new to this forum - my son borrowed his soon to be father-in-law's 2016 F150 over the weekend and came home last night engaged - we love his fiance' , but this morning when they went to return the truck - it gives a ENGINE COOLANT OVERTEMP warning - and will not run well

engine is stone cold

the engine coolent temp gage on instrument panel does not show any temperature - remember engine is cold -

we have tried to look for the sensor that could give this indication ALERT MESSAGE to the display as soon as the key is turned on - engine not started seems there is a cylinder head overtemp alarm that is being thrown - yet the engine temp gage (I am assuming it uses a different sensor) shows cold -

Am I correct that there are basically two sensors that are TEMP related? one which the ENGINE COLENT OVERTEMP ALARM uses and one that the gauge uses??

IF this is the case - where are these sensors located - we have tried to inspect from the passenger side in through the inner wheel well - , etc. but can not find it --

HELP please

Thank you to all

And of course to make matters worse we have found evidence of Red Squirrels having begun to build a nest and chewing - SO

The plan is: that once we find out which sensor would give the ALARM - ENGINE COOLANT OVER-TEMPERATURE

that I will get a new one - and hook it up to connector (assuming I can get the connection off, etc.) and then check to see after resetting OBDCII code (it shows as a P0118 by the way) and see if the ALARM goes away - IF not then I am assuming the wire has gotten broken or chewed on -

can anyone tell me where I could make a reading of the resistance (I assume the sensor is aa resistance vs temp type) at various harness connectors? to see if there is a reading there -

also for my instrumentation experience thermistors of the NCT type are typically 10K types....

Thanks you

scott.butler4

What engine do you have?
If its the 5.0 then replace the cylinder temp sensor with a OEM one, its on the back of bank1 at a angle, depending on year you may have to remove the intake manifold to do this.