Water pumps don't usually "suddenly" fail....they start to rattle and leak for a few thousand miles first...

My 300E M103 has the original pump working fine with 163k on it....if it was a car I drove on multi hundred mile trips all the time, I'd probably change it, but since it rarely goes more than an hour away, I'll wait till it shows signs of failure.

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'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)
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