[oil pan 4]

If you have any where near 100,000 on the engine those tight bearing clearances likely don't exist any more.
On my 8L engine I got the rod and main bearing clearances right at about 0.003 inches and I plan on running 10w-30. Industry standard for bearing clearance is between 0.004 and 0.006 and never less than 0.002 inches. Less than 0.002 the engine will sieze when you first start it up.
So I don't really believe the "tight tolerance" thing because no mass produced engine is going have bearing tolerance as tight as a blue printed race motor.
Manufacturers just don't have the time or money to pay some one to stand around for hours squishing plastigauge and swapping bearing halves on each engine intended for an economy car.