Quote Originally Posted by Hector
I currently use Castrol High Mileage 10W-30 designed for vehicles above 75K miles for my 200K-mile Mazda. I definitley see a difference in oil consumption when I use this oil compared to Mobil 1 10W-30 and Castrol Syntec. The high mileage formula doesn't burn as fast as the others. I don't mix oils in my bimmer but ironically, and lately, I've been mixing Castrol Syntec (1:4) with the high mileage formula in the Mazda in an attempt to get the best from both worlds.

Hi mileage oils tend to be formulated on the heavy end of their respective weights. I.E. 30 weight oil is 9.3-12.5 cst @ 100c, Mobil 1 10w-30 is about 9.8 cst, the castrol high mileage is probably about 12 cst. Also high mileage oils tend to incorporate some group V esters in their oil, as they seal swell. Technically they are semi-synth oils and most people on bobistheoilguy feel they have more synth than oils labled as semi-synth. I hope you aren't running 10w-30 in your BMW, it really wants a heavier oil.

Cary