Mine is from 1988, 400 000km, original manual gear box, original clutch, original engine, and one owner (me).
Range more than 80 000km with a set of tyres.
No rust anywhere.

Indeed there are that parts that get worn but all in all great.

A fantastic car and engine if well treated and maintained.

Same consumption as in the first days (between 8.8 to 9 liters per 100km -I dont know in gallons per miles).

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Keep us posted especially if your problem is solved
Present cars:
My car: E-class 420CDI, 2008, W211, V8, 180 000km

Wife's one: C-class 220CDI Sport Coupé, Euro, 2002, W203. 345 000km

Son's one: GLK class, 220CDI, 2009, W204

Sold: E-class 260E, 1988, W124, Wonderfull car sold after 489 000 kilometres of reliable services (engine M103, clutch, brake system and 5 speed manual gear box all original).

Sold: E-class, 320CDI, W210, 2000, 225 000km