IMO is the flavor of this discussion since no documents have been referenced, linked, copied, even exist.

The RPM argument doesn't make any sense to me, since the '90/'91 OM603.970 was already at a reduced max. RPM vs the 3.0L OM603.96, one of the reasons it only made 134hp vs the 148hp 3l engines. The later OM603.971 RPM was raised back up to within 100rpm of the 3.0 though, which increased its HP again. This along with advanced timing by 1* didn't have any more problems. The head was changed again, as was the head gasket, after the introduction of the .971 though. Does this support one poster's hydrolocking theory? I'd be interested in whether the head bolts were also changed in this case.

I still see this as only opinions and theory, with no conclusive answer, no test data, nothing at all. Anyone who calls this one is getting sand in his ears. Whether it was hydrolockiing from leaking gaskets, irregular combustioin from cetane, lugging from US market low-speed operation, sulfur reduction from regular to LSD to ULSD, weak rods, a rush to market, sunspots, we'll never know unless some real data emerges.

My experience with Mercedes-Benz Engineering was that nothing would begin production until the proper FEA was complete in critical areas, and FMEAs complete & analyzed, and any critical failures rectified. This experience goes through the introduction of the 60x series so I don't buy the rush to market theory, ... at all. I saw examples of the opposite, where an introduction was delayed pending engineering changes.

I do enjoy the theories and discussion however.

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Gone to the dark side

- Jeff