I'm with most other people who've heard for decades never to use a synthetic oil in a brand new motor ... and then Mobil 1 becomes factory fill in a number of high performance cars.
I'm not sure why Red Line still has this "do not use to break in" warning on their bottles. I think it was
Bob who said that Honda's break-in oil is heavily loaded with moly, a potent friction modifier.
So I don't know what to think about this anymore.
pedal, you might be right about the magnetic drain plug showing a lower iron rating than ordinarily might be, but other metals and worn compounds should be unaffected. As for bits caught in the filter or laying at the bottom of the pan, this is true of all engines. So, consider it a constant. The number which shows up in properly done oil analysis is a "relative" number ... and it is still useful.
And I pretty much agree with
Giles. That's
strong anecdotal evidence you have there ... but certainly not
proof of any kind. I've thought for a while that GM hasn't been putting a lot of quality and attention to detail into its pushrod engines ... especially those destined for trucks. They know that the design itself is so robust, it will usually outlast the rest of the vehicle once or twice over.
ZR2RANDO had spun a bearing before 100,000 miles and he blaims the "lightweight" 10W30 oil he was using. Like you, I'm pretty sure he was very good about regular oil & filter changes.
wtd was using Mobil 1 in his Chevy truck and was getting
miserable oil analysis results even though he was using a modest 5,000 mile interval and the truck was used mostly on the highway. A lot of us blamed the oil at the time, but it may have been a motor with slightly misaligned bores, poor quality bearings, etc ...
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Bror Jace