I was just curious who has the infamous "normal" 6.0 liter engine knock? My 6 liter knocks like crazy for up to 15 minutes after start up. It will also knock after the truck has been sitting for a half an hour, so it is not really a cold engine knock. I have about 6,700 miles on this engine and this is the second engine in my 2000 Silverado. GM replaced the original engine at 15,900 miles for the same reasons (knocking and tapping). I would like to show GM that there is alot of other people that have the same concern that I do. I don't feel that I should have to turn up the radio to block out the noises when you have paid over $32,000 for a new truck.