126 running hot?

[Mr. BILL]

I noticed in the last few days that on my '90 300SE, the temp gauge goes from 83 to 98 in a matter of a minute or two. Like if you are waiting for a light to change.

Waiting in a line, like a drive through, 5-10 minutes, it will go up to 105 or 110. As soon as the aux fan comes on,(about 110) or as soon as you start moving, the temp drops quickly back to 83.

The outside temp has been around 75. with the really warm weather coming, I want to be sure I'm prepared. What do you think?

Thanks