Generally speaking, my car uses/loses about a 1/3 of a quart between 3k changes. Now on cold start-up, I notice a tiny puff of blue smoke that disappears in a half second. In other words, after a half-second the exhaust is invisible. I assume some oil leaks overnight past the rings? Or what? At 158,000 miles I'm thrilled with my oil consumption, but just wanted to run this by you all.