BMW E36 Forum

My 325i seems to be running cool. When I am driving in town tempt reads middle of guage, no problem. When I am running on the highway the car is just barely out of the blue. I wonder if the thermostat is stuck open or just defective?

Is it the original plastic cooling system??
Its not hard to to check the thermostat, pull off the top cooling pipe going into the engine and there should be 2 screws holding the theromstat in place.