Well, I stopped by the Mercedes service center that is pretty close to my house - about 10 minutes away, luckily - and picked up 2 gallons of MB coolant! Hurray for me!! 22$ per gallon isn't too expensive, especially considering you don't have to change it THAT often. I will take it to my mechanic and have him drain the 'green stuff' his assistant put in there, flush it out, and refill with the MB coolant.

Now, the stuff from MB needs to be diluted 50/50 with distilled water, right? I'd like to know for sure so I can be non-ignorant when I go in early next week!

Thanks!

It should say on the bottle. If it says "concentrated", it needs to be mixed. If it says "prediluted", it is mixed.

does mercedes sell diluted premixed coolant? i believe all the sell is non-dilutted.

This is the coolant I bought today. I looked it over and I don't see anything about diluted or non-diluted. I do remember at the service center they mentioned diluting it 50/50, so I think that is probably right.

Anyhow, here's what I bought today...

Attached Thumbnails

   

that definately needs to be dilluted. see if the shop will flush the heater core and entire engine, using garden hoes or other method, it is very difficult to get rid of the green tint of the old coolant with a drain and refill, it took me a few flushes to get it out of mine, i disconnected all heater hoses, removed the thermostat (temporarily) to get maximum system flush

A complete flush is already on the docket - I'll be sure to let him know the MB coolant definitely needs to be diluted, in case he doesn't already know - but I feel pretty sure that he knows.

My '91 350SD has been running a bit hotter than I want it to - not OVERHEATING, but still pretty hot - especially with the A/C running, so my mechanic will be giving it a complete cooling system check-up next week - including a complete system flush.