Thermostat accuracy?

[Ali Al-Chalabi]

Hi,

I recently replaced the coolant and thermostat on my 97 C 280.

It is an 87C t-stat, but at first it took an engine temp of 95C to get it to open. With outside temps of 70F at highway speed, the engine runs 90-92C. With the old thermostat, which I figured I would replace for insurance when I had the coolant out anyway, the temps under these conditions were 82C.

My question is if there is some type of "break-in" with the t-stat. Will it eventually correct itslef to run at the correct temp or not? The engine temps at first were even higher, but they have since lowered 2-3 degrees. Or is this error allowable and no big deal?

Thanks a lot.