wierd noise from engine bay

I'm getting a pretty strange sound coming from my engine bay. It almost sounds like the sucking of a cold air intake but kinda of metal sound to it. Its either coming from the very front of the motor or from the pulleys. It is definitely something that changes with rpms so I know it's one of those 2 things. It doesn't matter if I'm in 4 wheel drive or not. Truck doesnt seem to be effected in any way but it's pretty loud. The pulleys aren't bent or wobbling but wondering if they get to wet does it wash of lubrication possibly?

We did just a substantial amount of rain, and after driving in it that's when I noticed. any ideas?

 

If it's when you first start the truck it is the air pump. Did it just start happening?

 

Yes just started happening last night. I drove home 1.5 hours and still making the noise when I pulled into my driveway

 

yes. any amount of water could cause them to "go".

loosen the belt and spin each one by hand to see if any of them have resistance.

rock auto has good ones under the gates brand that are sealed.

 

Those were my next 2 guesses.

 

I did get into some deep water last weekend. It was above my door jams and due to pushing the water it did take my front license plate off. I didn't notice it till last night though... Some good things to check though guys

 

Well found the issue. Idler tension pulley/bearing. Due to location dealer quoted me 870.00 to fix getting both pulleys replaced.... OUCH wasn't expected that from a little bit of water