Quote:
Originally Posted by Surly73
IMO - voodoo and guessing concerning air flow, thermostats that are "sticky" only in the morning and other stuff is far more "complicated" than bringing up a digital gauge that's readily available and simply looking at it.  |
I'm open to any combination of factors being involved. I agree it isn't always straightforward.
I'll give an example of a thermostat starting to open at slightly lower temperatures in an M57 diesel, (common weakness). Ambient temperature would make a difference to ECT. The colder the ambient temperature the higher the engine coolant temperature on steady speed driving. The mechanical thermostat is on the front of the engine, running in freezing air flows. Thermostat was being cooled from 'outside', slower to open and therefore held the coolant temperature (in the engine) slightly higher. In traffic ECT would drop back, exactly the opposite as you would expect for a failing thermostat, one which is failing to open position.