The temperature gauge on my ’93 300E fluctuates between 90 degrees and 100 degrees. When I am on the highway, it is pretty steady at about 90 but will climb higher during start and stop traffic. It never goes into the red. I’m hoping that it’s that the gauges are incredibly accurate but am concerned that it is something $$ like the fans are not turning so the car needs to be moving to have air forced through the radiator. The last time I had a radiator replaced it was on a Plymouth van (can I say Plymouth in a Mercedes forum?) and it was $500 then. I have only had the car a few days.