Technical Coolant Temperature Sensor x244 2.8 JTD Ducato

[IceVovo]

Hi Guys.

Firstly thanks for everyone's excellent suggestions previously.

I am still learning about this van....but getting there.

This is probably more at others who have MES???
My question is now about the
Coolant Temperature Sensor on my x244 2.8 JTD 2006 Ducato Maxi.

I am considering replacing it but at $50 here, only want to embark on this
if necessary.
I have MultiECUscan(MES) diags.

I loaded it to see the Coolant Temp Sensor(CTS) readings.
It showed me the Engine Temp and corresponding CTS voltage.
As the temperature increased, the voltage did drop.

Temperature Sensor seemed to be working...

But ... The Ambient temp here at cold was around 20 degrees C.
MES reading was 32 deg C at cold.
Calibration seems out by too much starting from cold.

So ...what are others getting with their readings?
Has anyone there checked the Engine Temp sensor at cold with a thermometer and MES?
How close was the MES reading to the outside ambient temperature?

Trying to establish how accurate the temp sensor should be to an external reading.....before just ripping out my sensor.

A faulty temperature sensor can affect fuel economy and reduce engine life also. Probably a good one to check anyway so has anyone else done this check?
I am very interested to learn how close the ambient temp is to the MES temperature reading of the sensor in the coolant at cold?

Thanks in advance.

 

[IceVovo]

Just an Update....

My CTS(coolant temperature sensor) is good.
Confirmed using MES.

I used MultiECUscan to read the CTS and log the Coolant temp vs Voltage in
realtime.
I was able to graph the results.

It compared to the Bosch CTS cdatasheet spec ...very closely.

So , I concluded my CTS was good and did not replace.

Note. I remeasured the CTS with MES after letting the van sit overnight for 7 hours.

 

[portland_bill]

When my Panda has stood overnight, both outside temp and coolant temp are close.
Once the engine has run, even on a very cold day, the coolant temp takes a longer to drop than the outside temp.
On a hot day, if run within a few hours, the coolant will still be hotter than outside, but if left longer, the outside temp can be hotter than the coolant.

If stood in the sun, we would expect the outside temp and coolant to be similar, once all the metal has warmed through, but dependednt on any wind, temp, direction and strength, the two readings may differ.

Does any of that help explain what you may have seen?

 

[IceVovo]

A. Yes. You are correct. Enthalpy. Means you will get slight variance from the ambient temperature to the coolant temp.
Take into consideration the difference.

I did need to do a repeat measurement under different conditions.

I was very happy to confirm my CTS was working properly even though my fans were not turning on. (confirmed with MES diag software)

Replacing the Bosch CTS cost $50 and sensors don't last forever in the engine bay.

But you can identify it is OK or faulty with MES.
It's good to know. Nobody wants to throw good money away.

I also turned my fans on/off with MES...proving the wiring and relay works.