5th starter since October.
 

Well today I removed dead starter number 4,getting another one will make five starters.I tried and ordered a Bosch rebuilt starter but all their staters for my car are built for a passenger side starter.Mine is on the drivers side.

I looked at a 300 this weekend that had the starter on the passenger side.

So yours is on the drivers side? Are you sure you are getting the correct starter? When they die, what dies in them? If you are chewing up the bendix drive (the overrunning clutch) you probably have a mucked up flywheel

The diesel engines use a much heavier starter than the gas engines.

Turned out to be the battery.But I replaced with new rebuilt.It looks like in photographs that this website sells the correct starter.However my money is tied up in Advance Auto parts.So if I have to replace again I'm going with a Denso.

I see alot of Benz at the junkyard with Advance batteries in them. I hope that is not a sign...

I buy Interstate Batteries for my cars. I've never had a failure in the 20 years I've been running them in my 3 vehicles. I usually get around 7 years out of them.

If your Benz is a diesel, then maybe you accidentally posted in the wrong topic? If I'm wrong, then I sincerely apologize. I dont know all of the Benz variations. Heck, I saw a 190 from the late 1950's yesterday.

I use Autozone batteries,this one is 6 years old.See these cars are diffeclut to diagnose because they have a starter cutoff for weak batteries
You never get to slow cranking to tell you.