You want to go to bob is the oil guy's site. We don't believe in extended intervals.

I would be more concerned about the cheap all-paper filter breaking up into pieces during these "extended" drain interval. Also, there's no point in risking engine sludge build up out of being lazy for not changing the oil. For a typical driven vehicle of around 14k miles per year, you'd still only change the oil twice at least. Don't put so much trust in that on-board computer's interval--it's marketing propaganda to say how low the maintenance cost is for those ballers that dump their cars for new ones after or just before the standard factory warranty runs out.

i agree with genuity, why try and get as far as you can and risk damaging your engine to save a little money? just change it every 5500-7500mi and you should be fine

Amsoil is not any better than the BMW recommended LongLife oils. You should not go beyond BMWs recommendations. Amsoil only recently acquiesced and actually certified their oils to industry-standards (ACEA, BMW LL, VW, Mercedes Benz, etc.) BMW and other manufacturers have been using synthetic for over 10 years; the only reason the name Amsoil and "extended drain" are associated is because they've been marketing it for longer than that.

If you look at lab reports from LongLife oils (or Amsoil if you can find them), the LL01 oils are down to marginal TBN numbers at the end of their recommended period. Amsoil will be no different. And be sure to use the LL01-specced oil, not LL04, which starts with lower TBN; US fuels have more sulfur in them and you need the higher TBN to last in the more corrosive regime with higher sulfur.

semockr said:

Search has not turned up anything about this topic and I would like to know how much time/mileage I can get out of a amsoil change. I change once a year in my 91 trooper and 95 voyager according to the mfr spec of 12mo or 24k mi. The defer to BMW for its extended drain interval and I havent seen any other than 15k mi for mobil 1.

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There are a BILLION oil threads online, here, everywhere. They all have peoples "thoughts" sprinkled in with a few facts. Rather than spend a ton of time reading, let me cut through the BS for you. Not only have I owned a 323 like yours that went 254k miles and my current one at 162k miles. I maintain more than 10 E46's (and countless other brands) for folks locally, including a guy with a 99 328i that has 305k miles on it and still purrs like a kitty. And here is what you need to know.

Can you go 15k miles between oil changes? Yes. Should you? No. Countless Blackstone Labs analysis show 7500 miles is indeed the sweet spot for these engines. If you want to push it, 10k miles would likely be fine too provided you run quality motor oil that is tried and true. So here are the ones to run:

BMW 5W30 (readily available online and at dealers for less than most others)
Mobil 1 0W40 (ok stuff, but has shown shearing at high RPM, given the car you have is driven by your daughter, it is probably fine)
Castrol 0w30 or 5w40. Both good, the 0W30 is my PERSONAL favorite.
Penzoil 0W40 Euro Blend

There are many others, but these are the tried and true so why bother deviating? Soon, I will have my first Blackstone analysis sent off running a 7500 mile interval with Castrol 0W30, I'll post the results.

Lastly, ALWAYS USE MANN OEM FILTERS!!!!!!!!!!!!!