Quick question, I see that these oils have manufacturer approvals.
My lack of understanding is why are these manufacturers putting their stamp on these particular oils. Wouldn't any certified oil be sufficient?
My first thought is these manufacturers are using different bearing materials and require this particular oil? why doesn't Toyota fall into this bucket of detail with their oils.?
I understand some of these oils have different additives but why doesn't Toyota jump in for their engines?
It leads me to think that these particular engines that require certain grade additives are especially sensitive in the cam and piston rod bearing Department. Can anyone clarify this. Thanks in advance
What does "certified oil" mean? API, ILSAC, ACEA? Those are very broad and somewhat minimal standards.
There isn't much variance in bearing materials for modern engines. They're almost all using bi-metal aluminum bearings, some are adding coatings but I've never heard of this affecting oil selection. Race motors still use tri-metal lead/copper bearings but this is irrelevant to manufacturer requirements.
Car manufacturers each have their own targets in terms of efficiency, wear protection, and motor-specific issues like LSPI, timing chain wear, intake valve deposit buildup, etc.
Like kschachn said, a lot of these standards include things like oxidation requirements, deposit buildup because some of these manufacturers, particularly euro marques have requirements for supporting longer change intervals than you'd get with a basic ILSAC GF-6.
I'm not sure what "certain grade additives" means. Grades are a measure of viscosity, not additives. The main requirements surrounding additives are typically surrounding SAPS levels (sulfated ash, phosphorus, and sulfur) due to emissions and deposit buildup. But this is a percentage or ppm requirement, not a "grade."
