S350 Turbodiesel (W140) reliability

[Nautilus]

Hello everyone

My Dad has decided to part with our W124 for its larger sibling, the S 350 Turbodiesel (W140 series), as we found a Navy-blue model well in our affordability range.

As the S-Class complexity and parts costs are well-known, I wonder what are the most common mechanical problems of a 12-year old W140, and in particular the OM603 engine.

The car will be tested prior to acquisition, but no diagnose can tell the future.

Also I would like to know what are the maintenance requirements and especially those of the 4-speed automatic transmission, as this will be our first automatic on hand.

There is also the possibility of a chiptuning, as there are some workshops which offer customized chips for the ECU for more power (being a turbo, although not intercooled, some sizeable HP can be gained).

~Thanks everyone

Nautilus