My oil consumption used to be ca 1/2 qt over 10k miles with Castrol Syntec 5W-50, and ca a 3/4 qt with M1 0W-40. 3k miles ago I switched to 5W-40, and, based on sound and smoothness, the engine seems to like that oil much better than the 0W-40. However, oil consumption is higher than ever. Keep in mind I've been driving the car pretty hard. Over the first 1k miles I added 0.8 qt, over the next 1k miles I added 0.7 qt, and yesterday, after 3k miles altogether, I topped off with 0.5 qt. That consumption is within what's considered normal for this engine, but it's still way higher that I've ever seen it. It's by the way very likely that my valve seals are not in very good shape, so that may well be a contributing factor. Anyway, oil consumption has been coming down, and I hope it will continue to do so. The oil on the dipstick looks still good, though it seems thicker and darker when cold. When it's hot it looks the same like when new. I'll definitely leave it in for another 2k miles.