Just my 2 cents... mine developed a chirp noise upon start up didn't go away and annoyed the crap out of me.
Took it to my mechanic he used the stethoscope and we found the noise coming from the water pump. Made sense as soon as the truck warmed up it would kick on and chirp. Was told lots of hellcat water pumps and pulleys go to shit. My truck has 21K miles. He said around 50k he sees them commonly shit to bed.
Took it to the dealer the tech said heard chirp coming from the water pump and one of the pulleys. Removed the pulley, it had the inner rubber seal gone bad and rust was showing. Replaced it and chirp was still going on. Dealer then replaced the water pump, chirp went away.
Dealer tech said HC pulleys do rust and I noticed the replacement pulley had a newer design possibly improved to withstand water corrosion.
Get your truck to a mechanic and try to hear where the noise is coming from. I bet you it's a rusty pulley or the water pump.