Quote:
Originally Posted by jvictormp
Have you guys heard of something about start stop system causing the pressure to drop when stopped, then when starting engine, letting the crank touch the main bearings?
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It's not the start/stop system causing this, it's simply a result of turning the engine off or on.
Most wear occurs on starting up (and I assume shutting off, perhaps to a lesser degree?) as their is no oil pressure initially (just a coating of oil). So on startup (initial second or so?), yes the crank is touching the main and rod bearings, this is normal for all engines. And is part of the reason for bringing in multigrade oils and having thinner cold grade ratings (the w rating). A 0w40 oil will circulate through the oil pump and bearings etc much more quickly than a 10w40 oil.
Of course A.S.S means starting happens much more often, so more wear caused there. In theory though the engine should have tougher bearings (and starter!) to cope with it (e.g the harder tin/alu bearings. They weren't only brought in for the EU lead ban). But tougher bearings are harder on the crank.
That said, although I haven't exclusively researched it, I haven't heard of A.S.S cars having engines failed earlier than normal, has anyone else? (Let's exclude the S65 from that question!
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