About a year ago, I purchase my '88 300E, which is my first MB (but won't be my last). The car looked beautiful and ran well, but had all the notable problems of the W124's (leaked oil, trans fluid, coolant from the radiator...) I spent most of this last year reading the posts to this site every morning, except weekends, and gathered a tremendous amount of diagnostic information. I have slowly purchased the parts I felt I needed and planned on having the work done over the winter months while the car was being stored. I am very please to report that after a new front pump and seal at the trans, in addition to all new seals/O rings and a complete filter and gasket change, the trans leaks have stopped. The engine received a new head gasket, valve cover gasket, valve stem seals, timing chain with all new rails and guides, waterpump and new Behr radiator. I happen to stop by my mechanic's shop when the head was apart and was pleased to see that there wasn't a carbon buildup in the head. I was very excited when I picked the car up so after a day of babying it, decided to test the work performed and drove it like I stole it. sure enough, the one part I did not replace, the thermostat housing, had issues and decided to separate into two pieces.
That updated part seemed to have escaped my research. A day later, its back on the road and everything is working great.
I wanted to thank everyone who posts and replies with their experiences. I have saved countless dollars by learning the common problems and the proper fixes. Thank you to all