Normal Coolant Temp ???

[tomm9298]

I recently replaced my thermostat, prior to the change my engine would NEVER reach 80* C. It would barely move off 40*C. Now that I have changed it seems to run about 90* C. The old thermostat was not stuck open??? I can't figure it.
After the replacement I let the engine reach 90* then loosened radiator cap and drove up a steep hill. Parked and put heat on max. I hope this burped the system. My thermostat is rated at 80* C. My thoughts are that at 80* it should open and run in the 80* range. 90* seems to be a bit high.

Thanx in advance.....