Great video Major! Quick question, I noticed your engine sounds like a couple of our XJs as far as the slight tick/light knock sound. Does yours go away after it warms up? Also what do you suspect it is?
These 4.0 engines are known for making noise at start up. Yes it is completely quiet when warm. I think it is a top end rattle, meaning lifters are not pumped up all the way and have valve chatter. If yours does this try taking one of the cheap harbor freight stethoscopes and touch the valve cover when cold and then go under and touch the oil pan and see which area is louder. Might make a great video for you!
