Mondeo Diesel - Low Engine Temp

[MikeTVR]

I have a 53 reg Mondeo Diesel (130ps) and am experiencing low engine temperature readings which show on the gauge (approx 70deg)and also cause the ECU to raise the idle speed to about 900RPM rather than the normal 750RPM. I have changed out the thermostat for a genuine Ford replacement and there is no difference.
The gauge looks to be OK because during short periods when the engine is under more load or if the heater is turned off the reading comes up to the normal mid point and no further.

I've had several Diesel Mondeos (02 to 06 company cars) over the years and they all had a very stable temperature reading.

Does anyone know of any possible reason for this low temperature ? I've heard that there is an auxillary electric heater but I can't locate anything and according to the Haynes manual this is only used in the early warm up to get the engine to 75deg.

Mike

[andy_quantum]

I'd take a guess at Coolant Temp sensor or sender being the problem, some electrical spray or a new sensor would sort it out

[MikeTVR]

andy_quantum said:

I'd take a guess at Coolant Temp sensor or sender being the problem, some electrical spray or a new sensor would sort it out

Andy - do you know if the ECU temp sensor is the same as the gauge temp sensor, in other words is there one or two sensors ?

I would say that the sensor is OK because I can predict when it will show the right temperature ie when the car is under load or standing still with the heater off.

Mike

[andy_quantum]

I dont to be truthful, the way I came up with my original answer was because my Elan was having similar problems and thats what it came down to

I can help by pointing you off to MEG? www.fordmondeo.org would probably have the answer if other posters here dont