There is an extremely long list of factors which could vary the answer to your question by a margin of more than 100,000 to 200,000 miles.

It all depends on maintenance, fuel quality, oil quality, driving style, ambient temperature and humidity, etc, etc, etc...

According the shop manager at the local dealer, a well mantained M104 engine here in the tropics should last at least for 200,000 miles. But, then again...

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A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]