Thread: Oil Change
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Old 01-17-2005, 12:41 PM
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F1Crazy F1Crazy is offline
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Mein Auto: '14 535iX '12 X5, '03 325
SLO Town, we've had the numerous oil discussions on this forum so I'm gonna make it short. The part of your owners manual about oil was written in 1999 when BMW started selling E46s. At that time there was no other oil on the US market that would meet BMW specs other than their own, hence the recommendation of the widely available and popular Mobil1 or Valvoline, the official supplier for BMW at the time.

As far as all synthetic oils being adequate it all depends on driving conditions. You can put mineral oil in and it won't destroy your engine as long as you change it frequently and don't put any stress on the engine. The major part of the BMW specification is that the oil has to be suited for extended intervals, the spec itself is based on ACEA A3/B3 specs. Approved oils are simply more robust, with higher High Temperature/High Shear viscosity numbers and additive package better suited to fight acid build up.

The most important thing in your oil choice is viscosity. I'm not saying to do this, but I'll bet any quality synthetic in a 5w-30, 10w-30, 0w40, or 5w-40 would not cause any problems. Most certainly you wouldn't want to run a 10w-30 or 5w-40 in the dead of winter in a cold climate, but that oil would probably be a good choice in mild climates where cold starts are not an issue. I've read that some members of the forum and others use 5w-50 or 15w-50, and I think that would be a mistake (as would 0w-20 or 0w-30).
I think you don't have a clear understanding of oil viscosity or SAE numbers for multi-grade oils. How running a 5W-30 oil in a dead of winter in a cold climate is different from running 5W-40? Both have the same Winter number (5) which means they will both behave like 5W oil at cold temperatures. Also, please explain to me why is it a mistake to run 0W-30 oil? I did it with an oil that met BMW LL-01 specs and have oil analysis to prove that it did very well.

BMW doesn't use special break-in oils but the cars that are shipped here from Germany are filled with a better oil than what we can buy here, I'd leave it for at least initial break-in period.
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