”Those old Mercedes diesels will run forever!” That’s what I constantly hear when someone who is a ”car person” sees or hears I drive an old Mercedes diesel. Usually I just smile and nod in agreement because they don’t want to hear about valve adjustments, multiple filter changes, purges, diesel fuel additives and everything else that goes into keeping an old Mercedes diesel running forever. ”Nope, you’re right, just pour whatever liquid you want into the tank, it’ll run. Sure.” That brings me to today’s car. An OM617 diesel that is half way to running forever with only a tick over 585,000 miles. Now since you’ve heard about these cars that are capable of doing a crazy amount of miles, let’s take a look at this 1980 300D in Scottsdale, Arizona.