[Brucelee]

Conventional DINO oil IS shot at 3K.

I use M1 in my wife's Subaru and change it at 5K.

Seems to work fine.

Originally Posted by donv

There is (or at least was) an incentive for car companies to set longer oil change intervals, from the EPA or similar forces in governments everywhere. Back when we had effective CAFE regulations and the like, there was great pressure to reduce the amount of not just gas but also oil consumed. An easy way to do this was lengthen change intervals. The same folks that figured out it was cheaper to not fix the Pinto gas tank problem probably also were able to model when the engine would fail, on average, at change interval x+y%, so the car company execs could please the EPA. I'm sure it was/is targeted to be at some comfortable point past the factory warrany period.

I experienced this the hard way with my first "bought new" car... an '84 Honda CRX. Factory change interval (just extended at the time) on that was said to be 5K miles (conventional oil). I had previously always changed at 3K on all the used cars I'd owned before, with good long engine life. Following the 5K on the Honda got me a smoker by the time it hit ~70K miles.

I'm back to a religious 3K interval on my conventional oil cars since and they've all lasted well past 100K with no oil consumption. I'm doing every 10K or min. yearly on the Boxster with M1. With the oil being recycled now, I'm not worried that I'm ruining the planet with this practice - quite the opposite. By having the car last longer, that is one less vehicle that needs to be made as long as it lasts, saving energy and other resources consumed in the mfg. process. And of course, fewer steep new car depreciation cycles for my wallet, too.