|Long Drain Intervals in a BMW|
|I have a BMW 325iC convertible. BMW recommends oil changes at very long intervals – 15,000 miles using synthetic motor oil. Do you agree that this is adequate for Southern California’s combined stop-and-go and freeway driving?|
|-- Scott Sherman, Valencia, California|
|The short answer to your question is yes, but keep in mind the responsibilities that you should fulfill. More and more automakers are realizing the advantages of synthetic motor oil, and specifically, Mobil 1™. While BMW does not use Mobil 1 as "factory fill," BMW does list Mobil 1 among its recommended lubricants, and perhaps more to the point, Mobil 1 0W-40 exceeds the BMW LL specification.|
BMW, and some other automobiles, now have sophisticated oil-drain-interval systems built into their electronic engine management systems. The combination of these electronic systems, better and even more robust engine designs, and the long-lived protection of fully synthetic motor oils allows these automakers to recommend such long drain intervals. There are two caveats, however. First, if you tend to use your BMW in a manner that could be considered "severe service," you should definitely consider shortening the drain interval from 15,000 miles. The second, and perhaps the most important, is that it is even more important for you to check the oil regularly. Modern engines can easily go 3,000 miles or more between oil drains without needing a top-up, but with oil drain intervals of 15,000 miles, it is much more likely that you will need to add a half quart or more between oil changes. Individual engines vary. It is also not uncommon for a high-performance engine to require a top-up of motor oil every 2,000 miles. (Most manufacturers consider anything better than 1,000 miles between top-ups as "normal.") In sum, yes, you can drive with confidence using Mobil 1 for such long drain intervals, but it is incumbent upon you to make sure that your BMW's engine always has a full lubricating system.