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Discussion Starter #1
I have asked this on here before but got few responses and there is a lack of knowledgeable diesel mechanics in my area so I decided to take a video of the noise my truck makes and see if anyone can give me any advice.


You will have to listen carefully but the squeal starts at about the 6 second mark.

Its a high pitched squeal that will not go away as long as im building or maintaining over 10psi of boost.


Thanks JB

VIDEO IS HERE
 

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Try the video link again...
 

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nvm...
 

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Im Superrrrr!
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kinda sounds normal to me....
 

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Discussion Starter #5
kinda sounds normal to me....
And it may very well be normal, this is my first Duramax after owning 7.3s for the last 9 years or so. You can hear the normal turbo whistle, then at about 10psi the whistle is converted to a squeal that reminds me of a squealing belt and it just doesnt sound normal LOL, but i havent driven an other LLY's to compare it to.

JB

PS the video really doesnt do the noise justice lol
 

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Ive listened to it several times and I cant really hear anything out of the ordinary.
 

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Im Superrrrr!
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My guess would be the vanes changing and thus resulting in a different sound.

I listened to it at least 10 times....but I'm sure its more hearable in person....

Just drive it til she blows lol.
 

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Discussion Starter #8
I should have my tunes from Rob in the next couple of days, maybe his magic will make it go away.:)

If not then Ill run it til it blows:rofl

Thanks for the responses guys

JB
 

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yea man that sounds weird. how it squeals for a second or 2 then goes away. sounds like something is loose check your downpipe to frontpipe connection
 

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Discussion Starter #10
yea man that sounds weird. how it squeals for a second or 2 then goes away
It only stopped because I let off the throttle, it will continue that as long as im on the throttle and boost is over 10 psi.

sounds like something is loose check your downpipe to frontpipe connection
That should be easily accesible from under the truck right? What kind of connection is it, a clamp or a flange? It has aftermarket 4" exhaust but it was on the truck when i got it.

thanks JB
 

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does it still have the stock lly mouthpiece mine did that before then i went with a lbz intake system and it went away ... other than that it sounds pretty normal to me
 

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I had a squeal in mine after a couple months of removing the egr. The elbow that went into the y-bridge has 2 o-rings that seal it(Hope I am using the correct terminology). The one had ripped off and the other was cut. It was from poor alignment. Maybe something to check out not sure if any mods have been done around that area but it sounded like mine did, other then mine started after 20 psi. Good luck.
 

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Discussion Starter #13
I had a squeal in mine after a couple months of removing the egr. The elbow that went into the y-bridge has 2 o-rings that seal it(Hope I am using the correct terminology). The one had ripped off and the other was cut. It was from poor alignment. Maybe something to check out not sure if any mods have been done around that area but it sounded like mine did, other then mine started after 20 psi. Good luck.

My EGR Delete kit will be going on this weekend, Im hoping to check over everything then.

A friend of mine said he could pressurize the system to check for any holes in intercooler boots, I will eventually figure it out lol.

thanks JB
 

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Discussion Starter #14
Update......

The Squeal was coming from loose bolts at the uppipe to EGR cooler, I found this as I was deleting the EGR.

I also had a cricket type sound in the cab at certain RPMs and Im almost certain that the loose bolts was causing that also.

I ended up taking the uppipe off and welding it shut as well as removing the exhaust manifold to remove the bolt I broke Noomore.

After this mod my turbo now sounds normal and the damn cricket has died and my truck seems to have even more power...so im a pretty happy camper.

Next up is installing my gauges, been looking today and I think Ill go with ultralite II's or Carbon Fibers in a overhead pod.....still cant decide.


thanks for the help guys I may just figure this DMax out yet :thumb



JB
 

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I also ran into this problem with a 05 here at our shop today. Smoke checked it and found a tiny exhaust leak at the rear of the passenger side exhaust manifold. Spooled up the turbo with our tech II and it was just a whistling away. Just another thing to look for!
 

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It only stopped because I let off the throttle, it will continue that as long as im on the throttle and boost is over 10 psi.



That should be easily accesible from under the truck right? What kind of connection is it, a clamp or a flange? It has aftermarket 4" exhaust but it was on the truck when i got it.

thanks JB
Im having the same thing happening with my truck all i have done is the egr blocker plate. ??
 

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My block plate has been in for 2 months now and it just started a really strange squeal while building boost hope that is all it is.:drink
 

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Hello... Trying to gather as much info on this topic as my 04.5' LLY is making the same squeal/screeching noise also. Only does it under load, which I imagine is while its making boost. Is it possible the bearings in the turbo are going bad? Besides it grenading, how will I know if/when I should replace it?

Thanks, Karl
 
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