Re: MOTOR OIL
When these flow restrictions present themselves, and they tend to more often with a fully synthetic filtering media because it's denser to start with, the filter is bi-passed to prevent oil starvation. That means recirculated oil. Thats not good either. The Purolator / Motorcraft filters have been proven to still be filtering quite well up to 8000 mi. whereas many others give out and resort to the bi-pass at 4 or 5K, without the driver knowing it obviously. So it's a good bang for the buck. No matter if you use a Tier 1 or Tier 2 filter, filtering technology still has a way to go yet.
There are many folks out there that run the entry level no name synthetic oils and, since synthetic oils really don't "break down" like a dino oil, all they do is change the filter and replace what oil is lost from the filter change. I've read about some who have exceeded 100K in this manner and the engine still runs very well with no failures. They surely couldn't have been filtering it with the cheapest Fram filter. (nothing but a screen) So using synthetic oils alone is doing your engine a big favor within itself.
Given even todays engine tolerances though, anything under 10 micros couldn't even stack straight up perfectly in a line 4 high to get hung anywhere.
GT
