Quote:
Originally Posted by Scharbag
Changing the oil every 1000 miles will not extend the life of an engine with improperly designed hydrodynamic bearings. If it is too tight, it is too tight. This not only applies to bearing to journal clearance, but also to rod side clearance. With the lack of quality control, shown by data collected by those who initially identified this issue, BMW built a bunch of really great engine with a statistical ticking time bomb.
Modern synthetics can run longer intervals. This is shown by oil analysis reports where people paid for TBN. Most people, myself included, change oil far sooner than actually required.
A quick review of Clevite's information discussing bearing failure modes will support the hypothesis that S65 and S85 bearing wear is indicative of oil starvation, not oil contamination. If viscosity were a major factor causing increased wear, everyone running 0W40 oil should be seeing much greater wear than users of 10W60. This seem to not be the case - or at least we have not seen a rash of 0W40 oil users with worn or spun bearings.
FYI:
Castrol 10W60 V@40C = 160
Castrol 10W60 V@100C = 22.7
Castrol 10W60 HTHS = 5.2
Mobil 1 0W40 V@40C = 70.8
Mobil 1 0W40 V@100C = 12.9
Mobil 1 0W40 HTHS = 3.6
Redline 5W50 V@40C = 130
Redline 5W50 V@100C = 21
Redline 5w50 HTHS = 5.0
Happy motoring.
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Never said it would have. Only that engineers were not involved in final decision of the OCI.