300D 2.5 owners.... I have two questions for you
 

Hey...

I just picked up my fathers new 1992 300D 2.5 turbo.
Two things that I see wrong with it and I need your opinions on it if possible.

When I preglow the car the glow plug light does not come on at all. It only comes on after the car is turned on. It will stay lit for about 1-2 minutes. Any suggestions ?

The car runs at 80 Celcious all the time except when I am at a stop. Air conditioning is off as well. Should I just flush the system or change the thermostat ?

Thanks

first problem with the glow plug light is one of your glow plugs is out. the car might have some trouble starting if you have more than one out, so maybe youve noticed that, its easiest to replace them all. the only way to find out which one is out is to test each one, ive never done it so i dont know how. if youre going to replace them yourself, youll have to take the intake manifold off.

the second thing doesnt sound like a problem at all, 80 degrees C is actually very cool. 100 is equal to 212 F, so 80C is fine. mine usually runs at 90C, but lately at about 100C, because of the summer heat. you only have to worry about the temp if its over 100, adn at 120 you really have a problem.