The M117 is a beast, with proper oil changes and periodic chain/top end maintenance they can go for ages. I know of a person who had a 380SEL with the M116 with almost 800k on it....3 top end rebuilds...and a few timing chains. The bottom end is robust and can go practically forver. In normal driving these engines also don't have to work very hard to move the car.....I can drive all the way to work and back every day under 2k rpm easily if I wanted in my 420SEL...

My dad's old 420SEL had 311k on it when we discovered the timing chain guides were near-death, so we ended up retiring it as a top end rebuild+chain etc was more $$ than the car was worth at that point (some rust developing also) Its been sitting around as a parts car, and if you charge the battery the engine will still fire up fine.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)