Loud Squeal at start up

[Mfsr2005]

Thank you. Ill look at tensioner

[Mfsr2005]

On 7/16/2020 at 3:06 AM, Mfsr2005 said:

My truck has 131K miles on it. After an oil change by the dealership. I started the truck the next day and noticed a very loud squeal from the engine. It goes away after about 20 secs. But if i drive and give it a good acceleration, you hear the squeal around 3500 to 4500 RMP.

So after much trouble shooting. I replaced the passenger side exhaust manifold bolts. 1 one broken and need to be backed out. Two others broke in the process of being taken out. Replace all 5. The high pitch squeal or whistle is now gone. No thanks @General Motors  or the dealership. They should pay me back for looking at transmission when they were told it was not the problem. 

[2014silver5.3]

My 2016 5.3 has the exact noise and still does it when I start it with the drive belt OFF. Any luck with your solution?

[2014silver5.3]

34 minutes ago, 2014silver5.3 said:

My 2016 5.3 has the exact noise and still does it when I start it with the drive belt OFF. Any luck with your solution?

I'll be dawned if mine wasn't broke in the same spot.