Quote:
Originally Posted by Armand
During cranking, there is sub optimal lubrication so wear is not just limited to the starter. Agreed on hybrids but in that case starting off is assisted by the electric motor and the engine won't have to work very hard. That isn't the case with a non-hybrid gas or diesel engine. You are not only causing more frequent cranking but you are also loading the engine while lubrication is not optimal.
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I agree that there could be sub-optimal lubrication, but the engine has no load on it when it is being started. My starter won't engage unless the clutch is pushed in. Same concept with an automatic, you need to be in neutral or park. Increased wear is traditionally associated with a cold start, not with the starting of an engine that has been running recently. If you stop for 30 seconds and shut it off, the oil will not all drain down. I noted in my response that the starter will wear more, but only due to increased frequency of use, not due to harder use. I am trying to remember the last time that I had to buy a new starter motor because it was worn out. I think it was in 1976, and even that was only because I was restoring a vehicle.
It would be interesting to know if BMW went to larger starter motors when they introduced auto stop-start on the four cylinders.
We also need to consider that idling is already an sub-optimal condition for an engine, it is in no way benign. Idling engines are not at peak temperatures, and can have incomplete combustion, with a resulting build-up of residues. Avoiding idling is treating your engine right.
I don't buy that starting more frequently is going to wear out a battery, as batteries generally last longer if exercised. If your alternator can not keep the battery charged, then that is another matter, but batteries usually wear out on time (often due to deposition) rather than with use.
Where I live, the city asks you to shut off your engine after 10 seconds, not 4. It is a bylaw infraction at 3 minutes of idling within a 60 minute period. I generally don't shut the engine off unless I am going to be stopped for 30 seconds, and even then not if I am in traffic as it becomes a safety issue.