The cause of oil leaks is questioned
 

Why do some cars leak oil from the rear engine seal, and others don't?

After owning several mercedes, I've realized that they have all had an oil leak. But, along came my current W124 E420 1995 with a mere 147,000 miles and there is no oil leak.

I can actually park on my concrete driveway, without leaving a stain.

Well, my question is simple. How do I keep it from developing a leak?

Special oil? No jack rabbits from red lights (me like the power of 8 cylinders)? Or what?

Thanks for the suggestions. I want to keep this gem clean and dry. ;)

Replace the seals before they develop leaks

Maybe better sealing material? better designs around the seals so that heat exposure is limited?

This car was probably serviced by a real Mercedes mechanic and not by DIY. He corrected the crankcase breathing system. This is 50% the problems with the rear engine seal leak. On these older cars don't use synthetic oil before 1998 because these engines where not made for it.

We picked up a 1988 300E from dealer my father was working at the time. Serviced there since new. That SOB always leaked oil all over the driveway until it was sold that way. Was not going to replace the seal in that car. Never driven with synthetic either.

Do you think the dealer has real mercedes mechanics? They work all on flat rate, when the car comes in for service they just do what it takes to get it out, and don't check this type of things. They don't have real mercedes mechanics. A real mercedes mechanic has his own shop and trained their mechanics this way. I know it from my repair shop where i bring my cars.

plrase tell me more
 

I'm thinking a breathing system would help the seals
But where is the breather (vent) that I mxy check it further.

Yes I learned of the car from my mechanic friend, who serviced the car for years. He is a real Mercedes mechanic. :-)

Not a huge believer in marketing...but I've had good luck with Valvoline Maxlife 10W-40 in my 1995 E320. It's not too thick in the winter and it contains some seal conditioners.

I run synthetic in all the cars.

M103 190E. Leak at timing chain cover. Common leak point regardless of oil type.
OM602 300D. No leaks.
M116 420SEL. No leaks.
OM617 300SD. Leaks at turbo drain, probably a few other places too. Common for leaks regardless of oil type.

You honestly think an Indy "real MB mechanic" isn't going to make a mistake or fail to miss something either? If you don't do it yourself it never gets done right. Indy's and dealers are incredibly crooked.

Not all of them are. The two indy's that I use are honest and fair. I've been going to the same one for our Mercedes since 83' and the same one for our domestics for nearly as long.