360 Tune Up
Lets do a couple scenarios.
As long as the heat going into the coolant can be removed by the heater core the thermostat stays closed.
Just making up easy to remember numbers in the illustration.
Lets say at 45 MPH the engine works harder and the coolant now has to get rid of more heat.
The radiator takes over and even with 90* air temperatures, it brings the coolant through it down to 100*F
And lets say at 65 mph 150 BTU per minute are going into the coolant.
Even if the heat exchange at the radiator is still good enough to bring the coolant down to 100 F, its not too surprising that additional energy transfered into the coolant would raise the temperature at the sensor.
At least that's how I see it. If it keeps creeping up while driving, that's a different story.
That's also where I was going with the coolant temperature at the radiator outlet. If its increasing on par with inlet temperature then you'ld be right to suspect heat transfer at the radiator has been maxed out. Whether thats due to coolant flow, or air flow or fins would still have to be figured out.
Lets do a couple scenarios.
As long as the heat going into the coolant can be removed by the heater core the thermostat stays closed.
Just making up easy to remember numbers in the illustration.
Lets say at 45 MPH the engine works harder and the coolant now has to get rid of more heat.
The radiator takes over and even with 90* air temperatures, it brings the coolant through it down to 100*F
And lets say at 65 mph 150 BTU per minute are going into the coolant.
Even if the heat exchange at the radiator is still good enough to bring the coolant down to 100 F, its not too surprising that additional energy transfered into the coolant would raise the temperature at the sensor.
At least that's how I see it. If it keeps creeping up while driving, that's a different story.
That's also where I was going with the coolant temperature at the radiator outlet. If its increasing on par with inlet temperature then you'ld be right to suspect heat transfer at the radiator has been maxed out. Whether thats due to coolant flow, or air flow or fins would still have to be figured out.