David and others,
The wife's 93 300E has 98k and my 89 has 146k. I did put a new battery in my wife's car last year and the last major problem it had was the infamous faulty engine harness that has plagued the 104 engines. MB took care of that (Thanks MB!). Prior to that the head gasket was replaced due to pouring oil out of the front of the engine. Once again MB took care of that too.
The last major problem that I had with the 89 was I replaced the valve stem seals and hydraulic elements 2-3 years ago.
Like PE Haiges I do ALL of my own maintenence. The only time I pay labor is if I don't have the equipment to do myself (alignments, tire mounting, etc).
I have two really good cars. That's why I want to keep them.
92 Volvo 740 Wagon aka "Mutt mover"