I gotta admit I was skeptical and generally don't believe in a fix in a can but I'll be dang. 09 altima that was burning through 3/4 of a quart every 1k like clockwork. I've owned the car since new and serviced it every 3750 just like the manual says, quality oil, oem or better filters. Now at 118k I finally did what Nissan couldn't with kreen. Added half to the tank and half to the sump and let my son run it 1k miles, mostly 80 on the highway to his college and back, changed the oil and hoped for the best. He just pulled back in and I was shocked when I checked the oil at 800 miles to see it maybe used a few ounces, actually not even enough to add but I still did. I'm blown away! I still have another quart and am unsure if I should do it again when it nears the last 1k on the current oil or if to much of a good thing is to much?