My water temperature remains normal most of the time. But when the engine
is working under load, such as when going uphill for a minute or more, water
temp rises to nearly the redline. I'm talking about modest hills here, no
steep mountains, and this occurs even in 70 degree weather. When the water
temp rises, I lose water slowly thru leaks due to increased pressure.
Otherwise, I don't lose water.
I recently had the radiator flushed and the thermostat replaced (I think).
The problem has improved but still exists.
Is this much water temp variation normal?