Quote:
Originally Posted by curtludwig
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I read somewhere (I forget now) that right after an oil change MORE wear occurs and the old has to break in. Said the carbon chains in the oil buffered better once they'd been beaten around a bit by pressure and heat...
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I lifted this from a known respected VW TDI Guru from
TDIClub
Although this applies to specific long life TDI VW507 rated motor oil, I think the basic premise of the oil's life is the same of all motor oils with mileage adjustments:
Quote:
From Drivbiwire of TDIClub.com
You break down the oils life cycle like this:
Phase 1: Detergants attack the internals removing accumlated contaminants, neutralize acids and force those into suspenstion in the oil. This period of time lasts between 500-1000 miles
Phase 2: During the first 1000 miles the oils viscosity provides the majority of the wear protection by virtue of the film it creates on the surfaces. This phase generates relatively high wear rates but due to the short duration this is accepted due to the removal of contaminants that could result in long term damage to the motor. Wear rates in the period of time are generally speaking 5-10ppm per 1000 miles.
Phase 3: Detergents are now used up and the oil additives are forming their protective layers in the "extreme pressure" regions of the motor. Now the oil additives are working in conjunction with the oil film and the wear rates drop from 10ppm per 1000 miles to around 1-2ppm per 1000 miles.
Phase 4: Longterm peace! The oil is operating in a period of equilibrium, the wear additives are placed, Oil viscosity is in perfect range for the engine, Dispersants are continually working to prevent soot and other contaminants from accumulating on the surfaces and wear rates remain between 1-3ppm per 1000 miles.
Phase 5: Oil run out, the oil during this phase begins to increase in viscosity (or thin in some cases), Extreme pressure additives begin to lose effectiveness due to increased concentrations of wear particles (VW tests out to 8%, most oil changes never see in excess of 2% after 30,000 miles). This is when you begin to see a rise in the wear metal formation in the engine. Often wear metals during this phase rise to the 3-8ppm per 1000 mile range. Notice that the wear metals being generated are still LOWER than they were in the first 1000 miles?
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