Well, to be honest, this board and the pentastar engine head problem has made me a bit paranoid. However , when my new 2012 JKU sits for several days, I get about 3-5 seconds of a tap at start up. It's only at start up and goes away quick . Everything else runs quiet. (for now) I have heard its the oil just coming up thru the engine a well as some "other reasons". For those who really know on this forum, can I have your advice on this . ?? Would appreciate your mechanical honesty.