high enough where your at a straight 40 weight might reduce some consumption, otherwise i'd run a 20w50, When running dino oils i always seem to notice the least consumption with castrol or valvoline on heavily worn engines and the most consumption with pennzoil. But if your using that much oil then probably none of these are going to help much, and if its bad valve guides causing it then you may find that you kill the cat converter pretty soon too. Bmw's recommended limit is about 800 miles to a quart, usually if you consume more than that there's a problem.
Originally Posted by Jon K