3k Mile Oil Replacement A Myth?!?

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Originally Posted by Poochmike

I'm curious if any of you guys have done any oil analysis? I have used Blackstone as cited in the article in the hope of pinning down a proper oil change interval. Using full synthetic, they still suggest my oil changes be performed every 2,500 miles or so because of increased lead content in my oil (they say from bearings). I have shown my reports to Dr. Dave, the resident oil expert, and he was not concerned with the lead numbers and we are currently trying a longer interval to see how the numbers change. Here is my latest report:
I would highly suggest doing a series of analysis, they are very useful.

You've touched upon one of the things about the Legend that makes it last so long. The Rod Bearings DO contain Pb (lead) unlike most cars during that era. That is why we almost NEVER see rod bearings go bad.

Another huge factor is the design of the oiling system. The legend (like all hondas and toyotas) spins the oil pump with the actual crankshaft itself, instead of through a coupling device that wears out over time. ( I had an oil pump drive go out in a 5.0HO ford 3 miles from home. There is nothing worse than all the sudden having 0 oil pressure). On the other hand, a LOT of v-8s oil "backwards." MOPAR v-8s and BBF 385 series (429/460) are two examples of this I can provide. Instead of lubricating the main bearings and the rod bearings FIRST, it lubricates the top end, and THEN lubricates the bottom end. So the bottom end has zero oil pressure until the top end is pressurized.

Over time, crud builds up in these passages, and eventually the bottom end is completely starved for oil.

also, if you have a 3.0 or 3.3L dodge, you should change every 3K miles because those things are notorious for the above mentioned problem.