I have a small leak but nothing that would cause me to go through 5qt's. I can run it all day, park it and get maybe a quarter to half dollar spot on the ground overnight. Being that it's a 99' and the common issue of burning oil in the early 3.5's I've settled on that it just burns oil. I'm surprised it doesn't smoke. Also seeing as I can run it for a long highway run (like my trip to Orlando last time) and no oil burning smell or anything but I have to check it when I fill up because it's gone down a bit. It goes hand-in-hand with the miles driven, doesn't matter if it's 3 months between changes or 2 weeks because of a long trip.