Do I need to replace my thermostat?

[Frenchy]

If you are going to replace the thermostat, make sure it is a factory motorcraft thermostat. Don't ask me why but most modern vehicles can't seem to operate correctly with aftermarket thermostats as they don't tend to regulate correctly. For what it's worth you are catching the telltale signs

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[Kawffin]

I did end up replacing my motocraft thermostat with a new one even though it had only been year since it was installed and it solved my issue. The old one looked just fine. My guess is, it was defective from factory.

 

[TJMarchand]

I did end up replacing my motocraft thermostat with a new one even though it had only been year since it was installed and it solved my issue. The old one looked just fine. My guess is, it was defective from factory.

I had the same experience, I have 118k and just replaced my factory one. My gauge acted just like the ops and it threw a p1028 code all of a sudden. New thermostat and everything is working perfectly.

 

[DHMag]

Reviving a dead thread, would it be beneficial to also replace the coolant temp sensor since the cooling system will be drained ?

 

[RangerBill]

Reviving a dead thread, would it be beneficial to also replace the coolant temp sensor since the cooling system will be drained ?

I don't see the need, if you are not having any issues.

 

[Frenchy]

Reviving a dead thread, would it be beneficial to also replace the coolant temp sensor since the cooling system will be drained ?

As mentioned there is no real need to unless you are having an issue with the sensor itself or if Ford issued an updated sensor to fix a problem.

 

[DHMag]

As mentioned there is no real need to unless you are having an issue with the sensor itself or if Ford issued an updated sensor to fix a problem.

I also had the P0128 code pop up while in tow/haul mode. In the engineer test mode, my coolant temp never got over 81*C, which is below the threshold. I was thinking it could be the sensor at fault also, but i had not seen any mention of them failing. Would a faulty sensor trigger a different code ?

 

[RangerBill]

I also had the P0128 code pop up while in tow/haul mode. In the engineer test mode, my coolant temp never got over 81*C, which is below the threshold. I was thinking it could be the sensor at fault also, but i had not seen any mention of them failing. Would a faulty sensor trigger a different code ?

That fault is likely due to a bad thermostat. You might want to replace the thermostat while the coolant is drained from the system.

 

[Frenchy]

I also had the P0128 code pop up while in tow/haul mode. In the engineer test mode, my coolant temp never got over 81*C, which is below the threshold. I was thinking it could be the sensor at fault also, but i had not seen any mention of them failing. Would a faulty sensor trigger a different code ?

Usually a coolant leak or faulty thermostat will cause this before a faulty sensor. Also the 2.3 has both a Engine Coolant and Cylinder Head Temperature Sensor. When things are operating normally the two sensors will be within a few degrees of each other.

 

[airline tech]

I also had the P0128 code pop up while in tow/haul mode. In the engineer test mode, my coolant temp never got over 81*C, which is below the threshold. I was thinking it could be the sensor at fault also, but i had not seen any mention of them failing. Would a faulty sensor trigger a different code ?

The code P0128 - sets when eng fails to reach operating temp in a specified time
Thermostat Stuck Open - most likely

P0125 if eng fails to enter closed loop in a specified time

So, either the CHT Sensor is not reading accurately, or the T-Stat is stuck open
as the CHT Sensor is the input for both codes.

 

[DHMag]

The code P0128 - sets when eng fails to reach operating temp in a specified time
Thermostat Stuck Open - most likely

P0125 if eng fails to enter closed loop in a specified time

So, either the CHT Sensor is not reading accurately, or the T-Stat is stuck open
as the CHT Sensor is the input for both codes.

Is the ECT sensor just for the gauge ?

 

[airline tech]

Is the ECT sensor just for the gauge ?

The manuals really do not go into detail on how all the temperature sensors interrelate into the PCM control.
But the gauge (display) comes from the CHT (If Analog) and from I understand (NOT CONFIRMED) is that the sensor only measures the temperature of the head (metal) so it does not touch the actual coolant.
The code you have list: Check Coolant Level, Thermostat, CHT and Gauge
It is a self-test after starting up - failure code
It is looking for the Thermostat Operation and does the engine reach operating temperature (fast enough)
It's using the CHT as feedback of input
NOTE: The manuals only cover and state that the (Analog Gauge) uses the CHT as a ref but skips where the indication comes from with the digital display.

 

[airline tech]

I guess I need to add this to my list of hands on learning with the scan tool for an answer of which specific sensor is for the gauge.
I know that both are used for the PCM and the fail safe cooling.

 

[DHMag]

I guess I need to add this to my list of hands on learning with the scan tool for an answer of which specific sensor is for the gauge.
I know that both are used for the PCM and the fail safe cooling.

Thank you so much for your informative post. The code popped up while driving home from work, about 65mph, in tow/haul mode, with 1200 lbs in the bed. Went to AutoZone to get it scanned and i presume they cleared the code because the CEL was no longer illuminated after that. When running through the engineer test pages, it only shows a historical code not related to this. It hasnt come back but i still plan on changing the t-stat regardless.

Another question, i currently have the pink (?) coolant, i will probably switch to the yellow. Should i flush and/or clean the cooling system before this switch ?

Again, Thank You for your wealth of information.

 

[Frenchy]

Thank you so much for your informative post. The code popped up while driving home from work, about 65mph, in tow/haul mode, with 1200 lbs in the bed. Went to AutoZone to get it scanned and i presume they cleared the code because the CEL was no longer illuminated after that. When running through the engineer test pages, it only shows a historical code not related to this. It hasnt come back but i still plan on changing the t-stat regardless.

Another question, i currently have the pink (?) coolant, i will probably switch to the yellow. Should i flush and/or clean the cooling system before this switch ?

Again, Thank You for your wealth of information.

Yes you should flush the coolant. What you have is not pink but orange similar to Dex Cool and it will cause problems. Get the motorcraft yellow from the dealer and change it out. Also make sure to get the factory motorcraft thermostat or you will have problems. It has been known across several manufacturers to have problems with aftermarket thermostats.

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