I've got a 92 Chevy with a 5.7 auto. It leaks oil so bad I can hardly bring myself to get in it and drive it. It does not smoke at all ever out the tail pipe. But I can't figure out where the oil is coming from and most of the time it doesn't drip at all. But sometimes if I get off the highway and look underneath its leaking from about a dozen spots like somebody poured a quart of oil all over it. But most of the time when I look underneath, even when I pull over on the highway quick, I can't see a single drop. I got some of the flourescent dye with the special glasses but if I can't even see a single drop, which is most of the time, I don't see how thats going to work. It never leaks from just idling, at least I've never seen it