Quote Originally Posted by Tone
Can someone please explain how the Exhaust Gas Recirculation system (tube or valve) being clogged has anything to do with oil consumption? Is it recovering partially burned oil from only the passenger side exhaust manifold and then redepositing it back in the intake trac where it is burned again or somehow seeps back down into the pan? Keeps the intake air charge hot? I just don't understand....

Very good question!

Amsoil

If the EGR valve malfunctions, engine performance is dramatically reduced. An EGR valve remaining in the open position will result in the engine stumbling or stalling at idle speeds. When the EGR fails to open, combustion temperatures cannot be limited, causing higher cylinder temperatures and an increase in NOx emissions. Engine ping or knock may occur, especially when the engine is under load.


In either case, drivability problems arise and NOx control is lost. The loss of NOx control results in rapid degradation of the engine's motor oil. NOx shortens oil life by increasing oil nitration and decreasing the oil's ability to neutralize acids (TBN) and maintain internal cleanliness, resulting in oil thickening and/or the formation of sludge within the engine.

Bob F Note: Increased Oil consumption is a resultant of higher cylinder head temperatures


Bob F
As far as the PCV Valve & the Isuzu 3.5 eng is concerned. It is my belief that if the PCV valve fails closed, then the resulting increase in crankcase pressure overcomes the drain thru of some oils thru the oil ring ( Isuzu design deficency) subsequently resulting in a rapid loss of engine oil. Catastrophic engine failure soon follows. Using a good quality fully Synthetic oil & changing the PCV & oil filter every 5,000 miles or less are my preventative measures to deal with this situation.