Not saying that I am doing the correct thing, but I have been driving my '92 300E M103 with a very slight head gasket leak for now going on 130,000 miles. I have crawled under the engine and watched the leak.

There is no contamination of coolant. I have to watch coolant levels and oil levels about every 500 miles. It's not burning oil, it's just leaks a little.

I will eventually get around to having the top end re-built and head gasket replaced.

Steve