chirping noise ,still not addressed

[6.2 man]

Well , my truck has been at the dealer for a week for the engineer to look at the chirping noise and also all kinds of electrical issues .Blank screens,flickering dash,very slow connection to answer a phone call ,climate controll ,trailer brake service promp, they made a 3 minuite video of the chirping noise and sent it in to be diagnosed. 

[ILSilverado]

On 4/2/2019 at 2:22 PM, 6.2 man said:

The dealership has diagnosed the noise to the exhaust flapper but will not order me a new exhaust,they are waiting on a engineer to come in but say he is very busy and it may take a while,well its been about a month and a half with this and no thing has changed,I have repeatedly asked them to order me a exhaust but for some reason they will not.

I had the whole muffler and flapper valve REMOVED! 

[Sierra Dan]

A quick shot of some penetrate lube will sometimes cure the chirping.

My belief is that the valve builds up a bit of rust or crust that makes it stick slightly now and then.

This use to happen on my Sierra and WD-40 Specialist Gel lubricant worked.

I am not plugging this product. It's just what was setting on the shelf in the garage and it is good up to 500 degrees.

[zzrsouth]

Any updates OP?  I've noticed a high pitch chirp or whine on cold startup lately

[ABEL AT4]

On 3/20/2019 at 10:59 AM, 6.2 man said:

I still have a chirping noise upon startup of the truck. 2019 GMC Denali 6.2 , sounds like a fan belt or serpentine belt but im told its in the exhaust valve built into the exhaust system. GM has told the servicing dealer who by the way has been GREAT to deal with that if they can find another truck to make this chirping noise that it is supposed to be like that. I told them NO ,if another truck makes a chirping noise that means they have 2 trucks that have a problem. I have requested to have the exhaust replaced and to speak with a engineer or regional representative to find out why they refuse to fix this issue .it has been well over a month but no response from GM ,This is becoming VERY annoying to have to spend this much time to fix a brand new vehicle with 3000 miles on it. Where is the service after the sale from GM .Things break,I get it ,just fix it already.  Sorry for the rant everybody 

I have a 2020 GMC AT4 6.2L and keeps making this squeaking noise when turning on and then it goes away after 15 seconds or so. It's becoming annoying, I haven't taken it to the dealership but I feel like they always try to do the minimal and not look into it in detail. Please see attached video. 

 

 

[JohnTz]

I have the exact same thing on my 2020 AT4 with the sport exhaust. I went to the dealer and checked two other trucks and they had the same noise on startup. Goes away in a minute or so. Something quiets down after it heats up. No idea what it is. 

[204Denali]

On 9/1/2020 at 11:40 AM, JohnTz said:

I have the exact same thing on my 2020 AT4 with the sport exhaust. I went to the dealer and checked two other trucks and they had the same noise on startup. Goes away in a minute or so. Something quiets down after it heats up. No idea what it is. 

Same on my 6.2 Denali, exact same noise and it goes away rather quick.  Doesn't sound like an exhaust sound to me, sounds as though its coming from the engine bay.

[Randolzj]

My ‘19 custom trail boss chirps when I am coasting down the road and I apply the gas slightly and then if I shift down manually I can get it to do it. I also notice it when I am on cruise control on the thruway and it applies throttle to maintain speed. Does anyone know what this could be? Almost sounds like a serpentine belt squeal. It’s hard to pick up on but you can’t stop noticing it. I would hate live with this sound on a brand new truck.

[s219]

On 9/21/2020 at 10:11 PM, Randolzj said:

My ‘19 custom trail boss chirps when I am coasting down the road and I apply the gas slightly and then if I shift down manually I can get it to do it. I also notice it when I am on cruise control on the thruway and it applies throttle to maintain speed. Does anyone know what this could be? Almost sounds like a serpentine belt squeal. It’s hard to pick up on but you can’t stop noticing it. I would hate live with this sound on a brand new truck.

 

I have the same exact noise in the video above on my 2020 Denali 6.2L, although I would not call it a squeak or a chirp, more like a metallic rattle or tinking (say -- ball bearings in a ceramic coffee mug).  It goes away about 10-15 seconds after starting up cold, or as soon as I put it in gear.  I can also hear it come and go quickly when auto-stop restarts the engine back up.  And most annoying to me, I can hear it when cruising down the road and accelerating with light throttle, just as you described.  With more aggressive throttle it does not happen.

 

All of these characteristics make me think it's definitely tied to engine load or associated vibrations, and could be related to something loose, something that twists, or even the exhaust.  I have yet to crawl under the truck to poke around, but the first place I want to look is at the exhaust system, exhaust shields, flappers, etc.

 

One time last week I heard it with the door open, and gave the truck a gentle rev.  That made the noise go away, but not before I could hear it change and seem to be coming from under the truck.  Granted, being parked on concrete that could have been coming from anywhere but it really seemed to be traveling from under the truck to my ears.

 

Pretty sure it's not anything serious but it is just enough to annoy me.

 

Edited September 26, 2020 by s219

[mdes0]

My 19 LTZ 6.2 has been making this noise for a while and has been getting worse. I thought it was the high flow cat y pipe I installed. Glad to hear it's not, but not looking forward to dealing with the dealer...

[mdes0]

I beleive I may have found the chirping issue. I think it is the idler pulley. I sprayed it with wd-40 and the chirp went away for a while. I'm now debating whether or not to bother with the dealer or just swap out the part. Its only 35 bucks and one bolt so not sure it's worth the time to bring it to the dealer... Anyone had the idler pulley replaced to eliminate the chirp and not had it work?

[Bratbowtie]

My 2020 GMC 6.2 chirp on start up, just came home  1 day short of 3 weeks , dealership replaced belt , alternator. , it was compared to another 6.2,they all do it, was what i was told they didnt tell me where the noise was coming from,  dealer worked i guess with GM , but what they done changed nothing. On another area about the issue was on here it was chimed in by a GM social media group to help , it really done nothing to help ,after over 2 weeks i asked for someone at GM come help dealer. Nothing was even addressed about it ,im disgusted...I have been very loyal to GM over the years , they really dont care , we are looking to replace my wifes Buick Enclave , probably wont be with another GM, or one of there China buicks either,  by the way,  my 6.2 Camaro doesn't make the noise ,my impala dosen't, my Buick Enclave dosent. My 69 Camaro with L/S motor dosent , its not normal just because you wont fix it , its called a blow off. A not happy customer 

[mdes0]

I pulled the main belt off mine and started it up. Still made the noise, so it's not the idler pulley. I wasn't able to get the ac belt off, dam stretch belts are a ******, even worse when your down to one arm. Had shoulder surgery a week ago. Guess I'll be going to the dealer for this after all.

[VGZPRT]

I had my truck 19 6.2 GMC inspected by the service dept. was told that it is the HPFP on the new trucks that makes the squeaky noise. Upon startup it goes through a self diagnostic and makes the noise. Sounds like BS to me but that's what they claimed. Truck only does it for about 15 sec on startup but not every time. Only the initial start for the day or if it sat for an hr or longer.

[childstoys]

Multiple threads about this now. Seems like a ton of ppl, mainly with the 6.2, are having the same problem. 

 

Would love to know the cause and fix... doesn't seem like GM gives 2 S4ItS about it though.