Has anyone experienced this engine noise '21 or '22?

[JameyLev]

I have been following all of these posts. I have a 2021 Escalade sport with the exact same issue. I am not hearing between gear shifts yet, service is worthless, the cold start is bothering me the most right now. I think i am going to try and have someone clamp open the flapper. Definitely need some help on this!

 

[Ferrari_220]

After research, it seems a lot of customers ('21 and '22s) have this engine noise without resolution from GM service. This noise is usually isolated to automatic drive, but isn't present when using manual shifting. I've resorted to the latter in regular traffic as the noise while in automatic can be a head turner. I've attached a video link of the engine noise someone else posted on youtube. Have any of you experienced this noise? If so, what was this issue? Was the issue resolved?

My 2021 Escalade esv dose the same noise did you find a fix yet. Its made the same noise since new and still after 43k miles

 

[Deuce16GMCs]

Gentleman,

I have 2023 6.2 Tahoe.

It suffers from the GM 6.2 Squeal Chirp.

It squeals when stopping at 14 miles per hours (this one can be cancelled by driving in L9 to deactivate the DFM).

It squeals during every gear shift (regardless of L9). Although very faint.

It squeals when accelerating from the mid 30's to mid 40's (regardless of L9)

It squeals when cruising on the highway in the low 70's (regardless of L9).

Have any you that have the squealing/chirp experienced it when cruising gentle around 39-40 mph and moderately accelerate back up to 45-48 mph. This happens in D or L9 so it's not a part of the DFM.

Your help would be greatly appreciated!

After further investigation, it appears the squealing from when accelerating from 39 to 45 and the squealing when cruising around the 70mph range is coming from the exhaust flapper valve. I can duplicate it in my driveway and make it go away by forcing the flapper valve open. I may have to fight this until they replace the OEM exhaust. What I don't understand is why is it still happening in L9 mode with the DFM off. Does the flapper still stay slightly closed when just cruising on a gentle throttle?

For the other squeals...

The chirping/squeal when cracking at the 14 mph range, and the auto/stop start, and the chirping/squealing startup is related to the DFM and spark retard per the bulletin.

I can eliminate the the Auto Stop start and braking squeal by driving in L9 and disabling DFM.

I really thought Escalades didn't have the issue since they have more insulation than the Tahoe and Yukon, but yesterday I was at a light and an Escalade came to a stop next to me and I clearly heard the squeaking. Then on the way home, I was riding next to another Escalade and opened my passenger side window and stayed beside them and when they came to stop, there it was again. Sucks.

 

[Chad G 1979]

The flapper nouse can be taken care of if you dont mind getting under your ride for a few minutes. Do a youtube search flapper disable. There are different ways to block it open so you can find something in your wheelhouse. I did it to mine within a couple days of oicking it up. I dont have any odd drone either with it forced open.

 

[Deuce16GMCs]

The flapper nouse can be taken care of if you dont mind getting under your ride for a few minutes. Do a youtube search flapper disable. There are different ways to block it open so you can find something in your wheelhouse. I did it to mine within a couple days of oicking it up. I dont have any odd drone either with it forced open.

Is yours a 6.2?

 

[Chad G 1979]

No its the 5.3. i think the process for the flapper mod is the same, the flapper may be in different locations on engine size exhaust setup.

 

[0x_2a]

Found a video of the flapper delete on the 6.2L L87, the sound is gone after delete. I'm going to try forcing it stay open.

 

[Z15]

There comes a time when you just have to give up and accept its a normal condition. It may be present in all of them but many don't recognize it or give a hoot. I can't hear anything from the video's that signals (to me) an issue. My 2021 Sierra Denali 6.2L is 3.5 yrs in service at 35,000 miles and I have not heard any abnormal noises and its been trouble free except of brake corrosion (salt use state). I turn off Start/Stop nearly every start and have DFM disabled with the Range. I'm not a fan of these modern engine gimmicks GM uses to save infinitesimal amounts of fuel. It only benefits the CAFE rating and causes nothing buy issues for owners (collapsed lifters etc). Just my opinion.

My neighbor informed me his 2021 Silverado CC 4wd 5.3L engine lost the cam and lifers at 80,000+ miles and left him stranded (on a Sunday) 300 miles from home. GM nor the dealer would not lift a finger to help defray the $8,500 bill. Life long GM owner who feels screwed.

 

[0x_2a]

Update! Sound Narrowed Down to Two Parts in the Exhaust Line

1. Flapper Squeak (easy fix, see below).
- Locking the flapper open stopped the very-high squeak on my 23 Yukon 6.2L L87.
- First check if your flapper squeaks by quickly rotating it (hot part, wear gloves)
- Take a video to see which way your flapper opens, rev it, mine is clockwise.
- After moving the coil tip to full-open, the coil will bulge. Tuck it under with pliers.
- How-to-DIY (undo by just moving the coil tip back)


2. Catalytic Converter Whistle/Chirp
Heard in the cats using a mechanic stethoscope, verified with chart readings. The right combination of exhaust flow rate and cat temp seems to reproduce the sound. Explains why performance/non-OEM exhaust upgrades don't seem to have this sound.



Fix - Options to make it go away
- Replace OEM with non-OEM cats
- Replace OEM muffler with non-OEM (changes exhaust flow rate)
- Replace OEM resonators with non-OEM (changes exhaust flow rate)

Notes:
- Reproducing varies with weather, air pressure, humidity, temp
- Occurs under combined conditions:
-- Catalytic Converter Temp between 1180-1200 degrees F
-- Exhaust Flow Rate around 22 gallons / sec

 

[GTPace500]

After research, it seems a lot of customers ('21 and '22s) have this engine noise without resolution from GM service. This noise is usually isolated to automatic drive, but isn't present when using manual shifting. I've resorted to the latter in regular traffic as the noise while in automatic can be a head turner. I've attached a video link of the engine noise someone else posted on youtube. Have any of you experienced this noise? If so, what was this issue? Was the issue resolved?

Mine does the same thing. 14mph and under as I slow. Also does it on every cold start. Saw this bulletin, but there's no way this is a normal noise:

https://static.nhtsa.gov/odi/tsbs/2022/MC-10225749-0001.pdf