I have a 300D and it runs at about 100 degrees on a warm day,,,is that normal???,,,and what type of oil is best when I change the oil??

as long as you keep up with coolant level, and it never gets much hotter than that, you should be fine on temp.......

As far as the oil goes, everyone debates as to which brand is better. I take a more neutral position. My outlook on oil is this, as long as you use a high quality diesel rated oil, and a high quality filter, you will be good. Some of the high quality oils are Shell Rotella T, Chevron Delo 400, Castrol GTX Diesel....

There are more oils out there, Im just too tired to remember them at the moment...... But as long as its a diesel rated oil, and a high quality one, you will be fine.......

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1983 Mercedes 300D
Atlanta, GA

I run about 80-85 c on warm days here (houston) on those days it is usually 90 to 96 F outside (yes I am running a working A/C), and if you consider the humiduty the 'heat index' temp is 100 to 105 F.

Given that, and that you are driving a bit north of me were it might be a bit cooler, I would suggest you might check you radiator - internal for flow, and clean it externally.

While running at just under 100 C is okay, at your location I would at least run a few checks (never hurts to be forewarned that there may be a problem in the making)...

I could be over reacting, but these are great cars and they need to be looked after. Have you added any water wetter to your radiator? FWIW - Enjoy, but check out the 100 c temp.

also check weep hole on bot of water pump for leaks. could be going bad.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.