The Nissan Path

2005 Pathfinder.

I start it up in the mornings, and it has a "sound" coming from the engine bay. It doesn't really sound like a common belt "squeal", but I could be wrong. The sound also gets quieter after the truck warms up for a while.

Could it be the tensioner?

Would it be best to replace the belt first and see if that fixes the noise problem?

Mine has the same, for lack of a better explanation "uncommon" belt sound.

After opening the hood and taking a closer look, it definitely seems as if it's coming from the belt area. There's a certain pulley that I need to investigate a little further to in fact confirm if it is indeed the tensioner pulley/assembly.

Could very well be the tensioner pulley/assembly. I've had to replace mine twice already. You can use a mechanics stethescope or a long screwdriver held to your ear to pinpoint the source of the noise. Could be an idler pulley, alternator, or other pulley.

Check out Nissan TSB NTB06-072a:

http://www.justanswer.com/uploads/fixur ... 6-072a.pdf