The motor has been leaking oil from various spots for the last 50k miles (I'm now at 124k), but the 0W40 does not leak more than the Castrol Syntec 5W50 (the "bastard" synthetic), which I used until last year. I have to add about half a quart every 2000 miles.

But 5k changes last me 18-24 months on my 2.8 as it's only a test-bed for mods. My sons 90S also uses Redline 30wt Racing and no leaks or usage between 3.5k filter changes and 7k oil changes.

Both cars have had the valley pan and head gaskets replaced due to oil leakage.

Oh and my 1.8T and my UrS4... yep, Redline 30wt racing and no leaks or usage between changes but the S4 gets 2.5k changes with filter. I HATE oil on my epoxied garage floor!!

While I live in a cooler costal valley, I commute eastward through hot inland valleys and/or deserts almost daily to do business.

I burn a bit more oil when I run 10W-40 full syn. in the winter, but the 20W-50 does not vaporize and burn off very quickly at all; at worst, maybe half a quart by 7500 miles--much of that through the breather tubes as my TB always has an oil sheen on it.

I think this will be the last winter for 10w-40, Lloyd at TDL recommends 20w-50 year round (for people in warm, non-freezing climates) based on his experience with the 12v's oil circulation system.

... until it started leaking small amounts.