Quote:
Originally Posted by MotoWPK
It's worthwhile to maintain perspective when discussing oil change intervals.
The OCI on my first car was about 2000 - 2500 miles, but engines and oils have developed significantly since the days of that '63 Triumph. And, engines and oils have continued to progress since 5000 or 7500 mile OCI's were standard.
10,000 mile OCI's are fairly common, the two different brands of cars I've owned prior to my Bimmers both having them. And these were fixed mileage intervals which are reasonably going to assume some average service condition. A condition based monitoring system replaces this 'one size fits all' OCI with one applicable to the service conditions of the specific vehicle and it's long been known that service conditions significantly affect the OCI needed. My 128i is almost never started where it isn't run for at least 45 minutes, and almost all of that is pretty gentle use. That the time to service indicated by the CBS is well beyond the nominal isn't surprising.
As another point of perspective, before my 128i I drove a VW TDI diesel for several years. The lubrication thread was one of the most active on the TDI forum and the argument commonly found regarding OCI was not that it should be less than the recommend 10K miles, but how it could and should be longer, and many of these opinions were based on oil sampling which was surprisingly common (at least among the forum members). A particularly intersting point supported by several oil sample reports was that concentrations of metals in the oil, a prime wear indicator, was greater in the first few thousand miles after an oil change, which indicated shorter interval OCI's would actually increase wear rates. And, these are diesels which contaiminate their oil at a significantly higher rate than modern gasoline engines.
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OCI's all vary by car, driving style and usage. One should really perform an oil analysis for their car and how it is driven to really establish when to change their oil (as I've said many times already).
I am pretty sure just about any synthetic oil could be run in an N52 engine for 3-5,000 miles and not have any problems (correct viscosity and weight at least) and 5,000 mile OCI's with a good oil will not increase wear on your engine.