Whistle Coming From Under Hood

I just bought a used 22 DC.
There's a strange whistling noise coming from the engine bay. It gets louder when I accelerate.

 

Does the truck have aftermarket air filters? Are the air box lids on correctly?

 

That's your washer fluid alarm. It's getting low. Not a big deal but don't let it run out or else your taillights will get dimmer.

 

I don't think it's the air box or the blinker fluid

 

My mpg is better when it doesn’t whistle, but sure is more fun to drive when it’s whistling!

 

Probably need to do chalk test on your tires.

 

I think it's the Tea pot don't forget to get the scones out of the glove box.

 

Myself? Why....................I'd crank the Zeppelin up louder.

 

The louder the whistle, the more fun it becomes.

 

Needs some new muffler bearings. It's pretty common. Maybe @ryanwgregg can point you towards a part number. Getting louder when accelerating is a dead giveaway.

 

TURBO!!!