A search on the W140 chassis will return several of the same type of resonses you are seeking.

From what I can tell, this drivetrain is very solid. Aside from the OM603 3.5L diesel, the engines in the 140 are fine. Common problems with the earlier 140 body cars are with the AC Evaporator (big $$$), closing-assist pumps (expensive, but not unbearable), HVAC control units (expensive, not terrible), and worn suspension parts (sometimes expensive, others not so bad).

A comprehensive extended warranty wouldn't be a bad thing to have on an early 140. Especially important would be a very thorough pre-purchase inspection by someone familiar with these cars and their related issues. Finding a trustworthy, knowledgeable mechanic may be an issue as well.

The common problems aside, the 140 is one heck of a car. Maintaince is on the high side, but if you can swing it, it will be a rewarding experience.

__________________
Lance Allison
Lance@LanceAllison.com

Current:
11 MB S550 4Matic, 55k miles, Designo Black/Black
14 Ford F150 XLT Lariat Crew, 73k miles, 5.0
Coyote V8 4x4. Black/tan.
09 GMC Envoy Denali, 5.3 V8, 4x4 SWB. 38k miles,
Jewel Red/Med Gray.

Gone:
87 MB 300SDL, 320k miles, Astral Silver/Blue.
98 VW Jetta TDI, 488k miles, Classic Green/Gray.
85 Olds 98 Brougham FWD, 4.3 DIESEL V6, 80k
miles, 3x Gray.

MBCA Member, Chicago Region