[Hawshad]

I was wondering what the average coolant temperature is, mine was 95-100 normally on a hot day but got up to 112 on country roads in mountains and the gauge was just above the half way is that normal or the car has a problem?

 

[cp-the-nerd]

That isn't overheating. As long as the gauge isn't continuing to creep higher, it's nothing to worry about.

 

[Hawshad]

Thank you very much.

 

[malibulady]

On a normal day mine holds steady at 196 F or ~91 C, but I've seen it go up to 208 F or 98 C when I'm running the heater hard.

 

[Knowledge]

Sounds fine to me. My coolant temperature usually hovers over 89-93 C. When I'm in the mood for spirited driving, I've seen it gone up to 105 C and even higher up to 115 C when I'm pulling hard uphill in mountainous areas.

 

[DrivenDaily]

"Running the heater hard" will actually help keep the engine temps under control. Using the heater doesn't add heat to the engine.

Pressurized systems will allow the boiling point to be raised above the atmospheric norm. For water, that's 212F / 100C at sea level, and lower as you go up in altitude. I don't have a reference to show the higher boiling point for different pressures, but so long as your system doesn't exceed that point, you'll still be flowing liquid. When it vaporizes at the boiling point, it takes up a lot more room and could cause the overflow to bleed of excess coolant to make room for the vapors.