I am having issues with over cooling.took a trip yesterday to devon 179 miles each way.motorway speeds 65/70 non stop each way. with nanocom live data for the first 40 miles my temp was 69.3.after 100 miles I averaged between 83.3 and highest at 80 was 87.3.i have a new all aluminium sport radiator,new genuine thermostat and gen viscous fan.also have a grill muff fitted.td5 manual,fuel used brim to brim 32.5.
worried will damage engine running to cool.
don't fancy long journeys without viscous fan.was thinking use the old viscous fan with half the blades removed alternate to keep balanced.views please

Not an expert. Mine now runs at 90 or so after about 15 miles. Just wondering if the system is pressurising properly. Possibly a. Faulty reservoir cap?

its the thermostats job to kept engine warm , i suspect a weak or bypassing stat ,

Under normal circumstances mine runs between 88 and 90 once warmed through. Goes up to 90 - 92 when towing a 1400 Kg caravan on the motorway at 60 mph.

Hi cambridgecockney.

Those temperatures look OK to me, especially at this time of year, in this country. Leave everything as it is.

The thermostat and Viscous fan are designed to control the temperature within certain safe parameters at all times of year in various countries.

If you have your heater fan switched on or even set on the red with the fans off you will cool the engine as it takes heat directly from the engine block.

You are NOT damaging your engine.

Search the internet and ask various garages and the greatest "true temperature" caused engine damage you will find is that caused by overheating, not over cooling.

Regards

Jonathan