Cooling issue on highway
Explain please. I thought a 180 stat opens at 180 letting fluid through
As the engine warms up the thermostat keeps coolant from going into the radiator.
At some point the engine temp is warm enough to start opening the thermostat.
If the cooling system is 4x oversized the thermostat will regulate the temp to be around the thermostat temp.
Most cars are not over cooled and so the engine temp will keep rising and the thermostat opening till it is full open. if you clime a hill the temp rises. If you go down a hill the temp lowers and the thermostat will start regulating the low temp of the engine again.
The outside air temp, the BTUs the engine produced under various conditions, the BTUs the radiator - fan - water pump can transfer to the air will set the operating temp of the engine.
Example,
100 deg outside air, the engine will most likely run a few degrees hotter than on a 70deg day. On a 32deg day the thermostat keeps the engine around the thermostat temp.
Back in the day when you drove through the Mojave desert there were ( are?) Signs telling you to turn your AC off for the next so many miles. This was to help prevent cars from overheating.
As for the fans running while you are at speed. My bet at some speed the airflow into the rad/fan is greater than the fan can do on its own and the load on the fan will be deminished, get a ammeter and do some testing. Test the current draw at a stand still and again at fwy speeds.
