Horrible Noise When Starting Engine

[WhackMaster719]

Hey guys, I was wondering if anyone could assist me with an issue I just started getting with my 06' Pathfinder SE. When the truck has been sitting in the driveway for about 12 or so hours and I go to start it I get a HORRIBLE noise when it first cranks over like something is flapping/grinding/and sucking for about 5 seconds, then goes away and everything is fine. Engine mellows right out and runs fine, gauges all show fine and I have already had it to a shop who could not get it to make the sound but checked it over and didn't see any glaring issues.... I actually took a video of the noise. Here is a link to it on YouTube: http://youtu.be/nxFIKsPc1t0

[mar1]

weird

checked the radiator shroud or any loose plastics near the fan?

[deermjd]

The inconsistent frequency of the sound makes me also think it is something related to the fan shroud. Odd that it only does it after sitting for a few hours. Maybe a bad fan clutch? You got me stumped.