AFAIK it's an 80C thermostat; my '95 E300 runs at about 90C on the gauge most of the time (but I don't necessarily trust it). The challenge lies in deciding which (a) thermostat, (b) temperature gauge sender, or (c) temperature gauge is correct. An IR thermometer is handy in measuring the temperature of the engine and radiator once it's up to whatever passes for "normal" in your or anyone else's engine.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970