Squeak Right Above Idle - Any Ideas?

[Wolf Island Diver]

Just noticed my ‘21 Ecodiesel has a squeak right above idle. I can’t get it to stay squealing. Doesn’t do it while dropping RPMs. Only does it increasing the RPMs and only just above idle. It sounds like suspension but it does it and the truck is stationary. Sounds loudest under the middle of the truck. Idler pulley bearing? Turbo?

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[Sandman 4x4]

Yea there’s no doubt a noise. I say try to remove the serpentine belt, without removing entirely when the engine is cold. The see if the noise returns? If so that isolates the source. Most likely the idler tension pulley. Search for Idler Pulley noise on YouTube. Good luck!

 

[Wolf Island Diver]

I’m now 90% sure it’s the butterfly valve sticking. My experience with belt noises is that they tend to manifest at higher RPMs. I’ve just heard so many belt noises over the years this sounds different, like sheet metal scraping. Like a rusty gate. I figured it may be a pulley bearing, rather than the belt itself, but if I open the hood and stand at the front of the truck looking at the belt, you cant hear the squeak/chirp over the valve train noise. It’s at the back of the engine and below. If I get out of the truck it’s clearly coming from under the driver’s footwell, so I think it’s exhaust or turbo related. None of the Turbo noise videos I’ve seen sound like this however. Actually a lot of Ecodiesel noise videos I’ve seen sound like normal diesel sounds to me.

I found the video posted by @Ulauma that sounds a lot like it and his was the butterfly valve.

I just hope I’m not going to start having nothing but problems now that I’m approaching the end of the powertrain warranty in the spring. Thankfully I’ve got MBI from Geico. I’m leaning heavily in the direction of just going up to CA in the spring/summer to get it fully deleted.

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