Quote:
Originally Posted by mahout
I forgot to ask if you see blue exhaust on throttle overrun, that is, when you slow down with the throttle closed? If you do, the engine is passing oil past the rings, if not, the inspection becomes more critical such as leakage past the oil pan gasket or other lines that only are in use during engine operation. Leakage past the oil pan only really happens on cornering, for example.
And don't just go tightening the pan bolts, they need to be done in order with careful attention to torque values.
As for the old 1 qt per 1000 miles that was applicable 25 years ago but not today with modern piston ring technology. Any builder tolerating even 1 qt per5000 miles would be laughed at. While it happens, as we can attest, the reason was always a mistake in assembly or bad ring (cracked or broken).
|
Usually, oil smoke
only on overrun is due to bad valve seals and/or guides. High intake manifold under closed throttle conditions pulls oil past worn guides/seals and into the intake. If you have worn/cracked/broken rings, or improperly seated rings, you'll get oil smoke not only on overrun, but on part and full load, and often on startup as oil will pool in the cylinder.
I completely agree with you that the 1 qt per 1000 miles criteria is dated and shouldn't apply to modern engines. That said, do a Google search on "normal oil consumption" and you'll see gobs of references on modern engines that cite this criteria. Fact is that anyone with consumption of 1 quart per 5000 miles will find the dealer not willing to do anything about it. I suggest going on record with it so that if consumption increases dramatically, you'll have shown that the problem was there from the start.