07 460 with 130,000 miles, radiator, fluid and thermostat replaced just a couple years ago.

I am noticing that the engine coolant display goes up alarmingly lately when accelerating.

And yes it does go back down when rpm's are steady.

I don't remember this happening or not prior to a couple months ago, senility?

Anyway, is this normal? Yes I do have adequate coolant, is this possibly a thermostat issue or what is this?

Thanks for your thoughts

 

No, it is not normal. I think you are correct in believing this is a thermostat issue. My guess is the thermostat is stuck so at high rpm's it doesn't open enough to allow for proper flow of the coolant.

 

Paul, thank you for your reply.

What is strange is this happens just increasing the rpm's a little from say 1400 to around 1700 while going up a slight incline?

 

Did you purge the cooling system off air? If you have an air pocket within the cooling system, it will cause overheating.