You don't mention whether the replacement vehicle needs to be a sedan or a station wagon or a van.

If it is to be a sedan, then the previous posts regarding the 1995 E300D are excellent as a recommendation for a vehicle that requires little maintenance, drives very well, and is comfortable.

If it is to be a wagon, then the advice of Engatwork regarding the 300TD is excellent. This is an older vehicle, manufactured up until 1985, and it is extremely reliable, provided that you buy one with maintenance records, low mileage, and pay a premium price for it ($5K-$7K).