Originally Posted by doughboy
I get your point mr pogle, so why not just change it every 6 then? I do for personal satisfaction.
I'm sure the oil sample will show it is ok relatively, but the 17000+ interval is not aimed at enthusiast owners (who know it is a marketing tool), or about keeping the engine perfect in tip top condition, its about striking a balance between low maintenance for the masses and increasing warranty failure costs.
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I agree with you.
The issue I am trying to address is that any oil change interval is a compromise. BMW's, your's, my mate's (who has access to free oil at work and so changes it when he has nothing better to do). The thing is that everyone is compromising on different things (cost, convenience, customer expectation, environmental impact etc.) and many of those things are not easy to objectively measure. Even when you can measure it, the actual compromise is highly personal. Maybe you can afford to spend 30 pounds a month on oil and I can't. Maybe you're only keeping the car for 3 years and maybe I hoping it will last 15. No offence, but "personal satisfaction" is not even slightly objective. I'm hoping to come up with my own compromise by having at least some facts and not relying entirely on anecdotes and unverified information.
The other problem (again not wishing to upset anybody) is that the whole oil-change thing has become a religion with many people confusing belief with facts and justifying their own positions with circular or baseless arguments. Conspiracy theories abound and utter nonsense is seriously put forward as undeniable fact. My mate changes his oil in almost total darkness because he believes that even very brief exposure to UV light damages synthetic oil. This is why it is manufactured in UV-free facilities and packed in containers which block UV light. He is a forensic chemist so maybe he is right or maybe he is mental.
I might start my own tyre-religion instead.....
BMW only recommend changing your tyres at 2mm to keep costs down for fleet operators. 2mm is nowhere near enough tread for high-performance, enthusiastic motoring so I change my tyres at 5mm.
a) A sad car-geek with more money than sense who is looking for a comfort-blanket/hobby/topic-of-conversation-for-the-pub?
b) A quality-conscious motorist who is looking to derive maximum performance from my not-inconsiderable investment?
Obviously (as with everything nowadays) there are no wrong answers.