My standard formula is Rotella 15W40 dino every 5K miles with a new filter and tire rotation at the same time.

I did run ONE batch of Rotella synthetic for a full 10K over this past winter to ease cold starts. Thought about changing the filter at 5K but decided to just let it go and watch for trouble. Never saw any. Back to dino for the summer; I've read all the miracle cure stories but my engine seems much happier with the standard thicker oil in it. Not to mention how fast I was having to add the thinner synthetic as make-up quarts to compensate for how much faster it can leak out than the thicker stuff.

If I were in the habit of running 10K synthetic oil cycles on a routine basis, I'd be very tempted to change the filter out at 5K anyway (or whatever halfway through my extended cycle was) just for the simple reason that synthetic oil doesn't stay any cleaner than dino oil across the same number of miles, it's just designed to handle being dirty better. Filters are so cheap compared to the cost of the oil anyway that I think it'd be cheap psychological insurance to change them even if there's no technical benefit.

That said, I've run 10K on the same filter before and can't produce any hard evidence of noticeable wear/damage OR the lack thereof beyond what I am more accustomed to seeing. I think over the life of the engine, the damage you'd do by running filters 10K, IF ANY, would be negligible compared to the cumulative effect of that many miles of wear that couldn't have been prevented even with magic pixie oil.

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL