Good stuff JCL always a pleasure to read your posts.

One note to add from the car stuff 101 textbook.... the engine isn't ready to beat on when you feel hot air from the heater vents, or when the coolant needle goes to 12 'o clock, or when the cool 4.6 cluster amber lights on the tacho disappear. Only after the oil is up to temp should we apply full military power to the right pedal.

Sounds basic, but in the interest of the topic I just wanted to throw it out there for someone that might not yet be aware.

Thanks.

Fully agree with you on the temperature issue. Oil temperature is most critical. Don't trust the coolant temperature indicator at all (it is a stretch to call it a gauge) since it is electronically buffered and as soon as coolant reaches a setpoint it goes right to 12 oclock.

If I had to choose between an engine designer/manufacturer and their recommendation, or the recommendation of a company selling oil, I'd go with the engine manufacturer. Especially when the engine company holds the risks of both the lease residual value, and the warranty/extended warranty fund. I have used Castrol Syntec, but I usually use the BMW 5w-30 made by Castrol, which isn't Syntec. I note that Mobil I now recommends following the manufacturer's change recommendations, up to 15,000 miles, unlike Castrol which is still pushing the 4000 - 6000 mile intervals that the motor oil industry has been promoting for years (although to be fair, they used to promote 3000 mile intervals).

For what it's worth: I traded in a 2000 BMW M5 for my 2006 BMW 4.4i X5. My M5 would need a quart of oil every 500 miles or so. My X5, thankfully, requires NO oil between oil changes. I love not having to think about it.

I do miss my M5, though.

depends on how you floor the accelarator, my friend! i would think that running your X like a race car will burn the oil out much faster, no?

I haven't owned an M5, but I have read a lot about oil consumption with M5 engines. I think the different manufacturing process, and use of break-in oil, make break-in more critical for long-term oil consumption. The 10w-60 oil is a difference as well. All of the above makes the M5 less comparable to the 4.4.

Adding oil every 800 km would drive me crazy.