Hi Everyone

This one is a bit of a puzzle!! The car is a 2006 Mondeo TDCi ST which has done just under 170k miles and came in to us with EGR issues which we have resolved. However what does concern me is that the engine seems to be running cold. On the SnapOn scanner once 'warmed up' the coolant temp senor is showing between 68 and 75 degrees C and 4.5 volts driving normally, and only goes up to about 79/80 driven hard. We have fitted a new thermostat and it has made no difference. I have tried driving with the A/C in eco to ensure the cooling fans do not come in, and again it is just the same. I thought it may be the coolant temp sensor, however on using an infra red thermometer on both the engine and top hose while running, with the CTS showing 72 on the scanner, I am getting 70 on the block and 68/70 on the top hose so this would appear to support the CTS readings. Additionally the temp gauge in the car mirrors the readings from the CTS through the scanner.

I have noticed that the ambient temp reading on the scanner is showing 37 degrees C and clearly the outside ambient temp is nowhere near this but would not think that this would contribute to the cold engine running. So - has anyone come across this before or got any ideas as to the cause and remedy? Any contributions are welcome!!

Thanks Roger