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Old 01-31-2013, 01:34 PM
jadnashuanh jadnashuanh is offline
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Location: NH
 
Join Date: Jun 2011
Posts: 733
Mein Auto: 535ix-drive GT
The computer lets you schedule an annual checkup, but the computer determines when the engine oil needs to be replaced. While I've had mine replaced free at the anniversary, at that time, the computer was saying service required at 19.5K - lots more than I had at the time. The oil change is triggered not only by miles, but by how you drive the vehicle. Lots of idling and short drives, it will shorten the recommended interval. I had a lot of interstate miles on it, which (normally) are quite easy on things. The big thing on any engine oil is how well the TBN value is holding up - you don't want the oil to become unbuffered and caustic. The oil BMW specifies should easily retain the buffers and additives throughout the time called for.

IMHO, there's no good reason to second guess the computer. The engine has a larger than normal sump, decent cooling, and they use a quality synthetic oil. While it might give peace of mind, I do not think it is really helping the vehicle. If you really bang on it, the computer recognizes that, and will shorten the interval to the next recommended oil change. If it were only an interval timer, that might well be a different thing, but the engineers have a decent idea of what's required on their engines...

Oil technology is not a stationary target...it continues to get better all the time. Short interval oil changes are holding with the past. If you don't believe this, take a sample and have it analyzed (I have), and you'd find you are quite safe relying on the computer's assessment. A decent test, checking the most important things costs about $25 or so and you get the results in less than a week. My old car called for oil changes at 3750 miles! I could easily go over 11K on it when using a decent synthetic. It cruised at over twice the rpm the BMW does, and put a lot more heat and wear on it (plus, I think the Castrol BMW specifies is a better oil than I was using). I'd only want to change it early if there were other conditions, the computer wouldn't know about, like driving on lots of dusty roads, for example. Normal driving...not a reason to change earlier. 10-years ago, this wasn't really the case on most vehicles and oils available, but today...spend your money on it if you want, but I do not believe you are benefiting the vehicle's longevity.
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