Re: Frequency of Changing Oil & Fuel Filters
When it comes to engine oil advice, even from the most respected engine makers, it pays to bear in mind what happened to the entire Detroit auto industry, which basically was the entire US auto industry, in the 60's.
If you owned a Chevy, Ford, Chrysler, anything made in the US and sold by a US franchised dealership, you were told that your warranty was VOID IF ANYONE EXCEPT THE DEALER DID THE OIL CHANGE. On the schedule and with the products that the dealer recommended.
DIY and your engine warranty was void.
That enlightened behavior was taken to the US federal court system, who ruled the behavior to be illegal competition against trade. As a result, today, you can use any damn oil you want, however you want, and the engine maker has to prove that your actions damaged their engine, or else they have to honor the warranty.
So much for the objectivity of engine makers, one and all. They want to sell engines, sell service at their franchises, and generally, they are engaged in a zero-sum gain, where they only make money if they can take it from you.
Sometimes the players have incentives you'd never think about, and the oil companies actually pay a premium to have their oil loaded in new engines at the factory. The same way that beverage companies pay supermarkets and bodegas to get the best placement on their shelves.
But if you look at the objective tests, or have your own oil analysis done, funny thing, no one has disproved the claims that the synthetic oil makers have been making. And most of them say right on the bottle, that they will make good on any engine damage found to be caused by their product.