Flippinb1

Almost sounds like a fan blade hitting on something for about 1 to 2 seconds then it stops. Only happens after it sits up for a while.. Gonna check it after work, but anybody had this happen are any ideas?

13'TwinScrew

I'd guess the obvious thing to check is the fan. With the truck OFF reach down where the fan is and see if there some play or wobble. If you are under warranty take to the dealership. A video on start up of what you are hearing would help tremendously.

93Cobra#2771

iTrader: (2)

Vacuum pump running.

Flippinb1

Vacuum pump...y would it make this noise?

ship it

Secondary air pump maybe? It's for emission purpose. It usually kicks in first you start and stops after while.

BCMIF150

This answer is right on. I hear mine when I start up as well.

Flippinb1

The truck only has 45,000 miles on it. Vacuum pump shouldn't be going out and making a loud noise like that??? First thing, I'm going to check the radiator fan when I get home... But thanks for all the suggestions and keep them coming... Will post results later!!

93Cobra#2771

iTrader: (2)

It shouldn't be super loud but you can hear it at times. Sounds like what you are hearing is really loud. Might want to get it checked.

murdr

Ahh, i am glad you posted this because mine does it too! Only every so often but if have noticed it. Its a very bad sound.

Flippinb1

It didn't happen again yesterday are this morning, spun the fan blade by hand yesterday and didn't notice any rubbing? Gonna take some videos of start up to see if I can catch the problem!