Sure, there are other factors involved in the creation of ring deposits. But an oil that is way more volatile can certainly contribute to what goes on with the ring pack deposits. The ILSAC, API, GM dexos and ACEA specifications have set the max limits for Noack (15% or 13%) most likely based on the kinds of deposits they see in the qualification testing of motor oils. Higher Noack can also contribute to more intake valve deposits as the vapors get sucked through the PCV system and into the intake manifold to then go past the intake valves to condense and leave deposits.That’s true. I suppose it’s more of an issue with high volatility oils creating deposits in the first place, but not every engine will suddenly begin using oil just because the Noack test is on the higher end of the “passing” grade. Engines more prone to deposits? Sure. But regardless of the actual test result for Noack for Valvoline Restore and Protect, it clearly isn’t causing consumption itself. If it were, those engines getting a reduction or elimination of previous oil use would still use some, I would think. But I’m sure there is more nuance here I could be missing or specific use cases.
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