In terms of overall long term repair/maintenance costs, the Mercedes C-Class is one of the least expensive "luxury" cars to own. Huh?
It depreciates less, and that's a biggie. But, as the miles pile on, things do break or require maintaining, but less so than most makes.
A Lexus ES300 with 250,000 kilometers (150K-miles) is a pretty tired car. I know a few owners with that kinda mileage, and they are facing some steep repair bills for suspension components, severly worn leather, charging system repairs, etc. Not unusual on ANY car with that odo reading.
The head gasket failure on the 1996 C220 is surprising to me. The M111 DOHC engine seems to have a very low failure rate for the head gasket, despite it's similar construction to the M104 engine.
Also, the AC compressor AND PBU? Hope no one's "throwing" parts at your car. The AC compressor is the variable pressure design, and has proven to be the most reliable system yet.
Maintaining any older car can come close in cost to the monthly lease payment of a new car if you're fussy. That's why people don't own their cars for more than a few years. I know a handful of C-Class owners that have kept their cars until past 250,000 kilometers, and they spend money keeping the cars in perfect condition, but no more than a Lexus owner.
1998 C230 "Black Betty"