running synthetic oil change interval?

[///M42 sport]

I've been running mobil 1 for a while on my m20. Havent really decided what interval to change my oil yet. 7k sound about right?

[ck_taft325is]

I don't like going above 5,000 no matter what the oil says. I start to notice a bit of a difference in how the engine handles itself after 4,000 despite being full synthetic.

[Cyrix2k]

It wouldn't bother me running it to 7k. Synthetic doesn't break down the way dino does, it's the additives that wear out but it takes more than 7k for them to deplete.

[KenC]

I'd be more worried about the filter at 7k

[MR 325]

3k for regular, 5k for synthetic.

[devon.818]

7k is the limit.
i'd feel safe at 6,500.

[E30MACK]

i dont go past 5k ever...even with synthetic i change it between 3-5k.

[browntown]

It's all a guessing game really. If you were really into it, you'd get an amsoil bypass filter and test the oil occasionally to see if it needs changed.

Both my fiance's honda and my subaru spec oil changes every 7500 miles and that's with crappy ol' dino oil.

There is some real good reading at bobistheoilguy.com

[Cyrix2k]

It's all a guessing game really. If you were really into it, you'd get an amsoil bypass filter and test the oil occasionally to see if it needs changed.

Both my fiance's honda and my subaru spec oil changes every 7500 miles and that's with crappy ol' dino oil.

There is some real good reading at bobistheoilguy.com

Yeah. And something tells me the m20 can take a bit of abuse. Mine looked pretty good inside and I can almost guarantee it was not taken care of. I know under my ownership it saw the cheapest oil I could find regardless of grade. I ran everything from 5w-30 to 15w-40. In my 540, I run 10-15k mile OCIs on synthetic. I was running less and the oil coming out looked as good as the new oil going in. I know that may not be a good indication of the oil's condition, but the factory OCI is 15k. Also read this: http://neptune.spacebears.com/cars/stories/mobil1.html

[MR 325]

The low cost of an oil change is worth doing it more often.

There's no research or test filters needed to prove this.