Jump to content

Recommended Posts

Posted

I have a new 2019 denali 4 door 6.2, it just turned 2,000 miles and it has a chirping noise under the hood at start up most of the time.It sounds like a belt making noise and lasts for about 30 to 45 seconds .Took it to the dealer and they are saying it is in the exhaust and that GM is stating that it is normal. I have owned a lot of vehicles over the years and never had one or heard of one thats supposed to chirp for a while when started. Anybody else notice this also

Posted

On the 2014-2018 K2 trucks like mine, the Adaptive Exhaust Valve A.K.A. exhaust flapper slightly before or after the muffler produced a Chirping

noise on startup and also during warm driving when switching from V4 to V8.

Some trucks have it, some do not.

 

Posted

I believe I have the same noise.  My dealer said “could not duplicate”.   I can hear it sometimes when going down the road if the radio isn’t too loud.  

Posted

Are there any negatives to clamping it open? Also, how does it sound open? Specifically, on the highway. I could hear mine. While it really doesn’t bother me, it sounds like the truck is cheap


Sent from my iPhone using Tapatalk

Posted

With it clamped open the truck will be a touch louder, and you may get a hellicopter noise when it drops down from 8 cylinders.

Sent from my Pixel 2 using Tapatalk

Posted
Definitely not looking to sound like a helicopter. Thanks


Sent from my iPhone using Tapatalk
I think the point was this was for troubleshooting to eliminate if the chirp was coming from the adaptive valve, so I would not be worried about the chopper noise.

Sent from my Pixel 2 using Tapatalk

  • Haha 1
Posted
On 3/8/2019 at 6:44 AM, 6.2 man said:

I think your right on the exhaust flapper , mine does it but my buddies does not . 

This sounds like a great excuse to buy a cat-back...

Posted
I think the point was this was for troubleshooting to eliminate if the chirp was coming from the adaptive valve, so I would not be worried about the chopper noise.

Sent from my Pixel 2 using Tapatalk



I understand that. Difference is I would hear the helicopter while driving my long commute to work where as I only hear the chirp from outside the truck when I’m stopped or with window open. I guess ultimately I have to try it out


Sent from my iPhone using Tapatalk
Posted

I have my 16 clamped open and tuned to turn off afm so no helicopter or chirp. Still pulling over 20 mpg at 70 mph with mud tires. If the adaptive valve is rattling or chirping the dealer may replace it under warranty. Mine has been replaced twice so far but the rattle always comes back.a180a1421588992c666b7de776986f70.jpg

Sent from my Pixel 2 using Tapatalk

  • 2 months later...
Posted
On 3/9/2019 at 7:41 PM, Thejet07 said:

 


I understand that. Difference is I would hear the helicopter while driving my long commute to work where as I only hear the chirp from outside the truck when I’m stopped or with window open. I guess ultimately I have to try it out


Sent from my iPhone using Tapatalk

 

I bought a new 2019 GMC Sierra SLT 6.2 about a week ago. Had the stock muffler, as well as the adaptive valves in front of and behind it removed.

 

Had a Flowmaster 50 Delta Flow Added for a nice deep tone to enhance my driving experience that would not upset the neighbors. 

 

I still hear a chirping sound on a cold startup and when the truck kicks off at a red light and starts up. I know jack sh*t about engines or any of this. I just love trucks... and hate chirping. The chirping reminds me of the exhaust of the VW Beetle from the 70’s. Thoughts?

Posted
57 minutes ago, DKSJLTrucks said:

I bought a new 2019 GMC Sierra SLT 6.2 about a week ago. Had the stock muffler, as well as the adaptive valves in front of and behind it removed.

 

Had a Flowmaster 50 Delta Flow Added for a nice deep tone to enhance my driving experience that would not upset the neighbors. 

 

I still hear a chirping sound on a cold startup and when the truck kicks off at a red light and starts up. I know jack sh*t about engines or any of this. I just love trucks... and hate chirping. The chirping reminds me of the exhaust of the VW Beetle from the 70’s. Thoughts?

Yep.  I have the GM cat back and hear the chirping too (on cold starts).  Seems to go away when warm.  

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Latest Articles

  • Posts

    • www.enginelabs.com/news/what-i-learned-today-bearing-clearances-vs-oil-viscosities/     www.enginelabs.com/news/oil-viscosity-can-the-numbers-be-misleading/ The Big Lie… Coming full circle to the reason Lake discusses the Porsche engines in particular. Based on the 2000 samples in the SPEEDiagnostix database, increasing the oil viscosity in these engines, even those run on the track, showed no significant difference in results.   The smoking gun was in the oil chemistry. That is where the data shows higher instances of more wear. Molybdenum was the key; the higher the amount, the less the wear. Speed postulates that higher viscosity oils have more thickeners to artificially inflate their viscosity numbers. These thickeners lose viscosity under shear, and the result is that not all oils of the same viscosity have the same shear stability.   Having enough viscosity is the most important characteristic, but according to Speed, once that required viscosity level is reached, additive chemistry matters more than additional viscosity. Speed also states, oil pressure problems on the racetrack aren’t a viscosity problem; it’s an oiling system problem. Running a thicker oil is just a band-aid for an underlying oiling system problem.
    • Can it still be Assembled II?   Viscosity on the decline by various means. Heat on the rise making that worse. Engine RPM in the tank. Smaller motors with more boost trying to emulate an electric motor. Full torque, zero rpm. Then we will triple the OCI. Argh.    But wait....there is more. LSPI has pushed a shift from Ca to Mg and as that cost more PLUS the run to lower sulfur compounds the TBN is moving in the wrong direction for the increased OCI's demanded.    That not being enough to placate a demand for a parameter they can't measure the other sulfur bearing compounds are also under attack. That would be zinc and phosphorus sulfonate compounds. To some degree those are being replaced with boron esters and others, i.e. titanium ect. All of which have shorter service lives. And there there is the "Secrete Sauce" marketing for AW adds that 'Can't be detected by UOA's" but trust me because I (the blenders) never ever lie.    Spoiler alert; ALL additives are sacrificial! Smaller amounts of the old blended with less robust versions of the new do not equal longer service lives. So what are the blenders recommending? Wait for it.......   MOVING THE GOAL POSTS! OMG      Let's declare the long standing TAN/TBN crossover irrelevant and tell people that soot is a great 'graphite' based lubricant which can aid tribo films. Wait, what? Let's declare that the standards used for oxidation and nitration were to conservative and can be expanded. Let's tell them that because GDI fuel dilution, although being a VISCOSITY KILLER and an acid generator is actually okay because we have better base oils that limit viscosity failure limits. (Said knowing this is measured in fractions of a centipoise and in bases not commonly used in shelf oils)   Lying from the heart is not just the new normal but we have a public, a very young public, that is so ignorant of the facts and so sure of their "RESEARCH" into AI driven models base in regurgitated  instead of scientific research based unvarnished, peer reviewed FACTS that the incoming guard is loosing their grip on reality and the OEM's are tickled pink while the blends bend the knee.    You have an ever limited set of tools to work with. And sooner or later those will be taken from you as the API and the EPA strangle the last remaining fluids from the system. What you have left is your wits. If you care to use them.    At some point in the very near future it will not longer be possible to do "What is best for the machine", and be replaced with "The best you have access too". You WILL be rewarded with half the life and twice the cost. That isn't that hard to predict.         
    • I trust you saw the other comment where he knew what he was talking about !. Yes, these darned newer vehicles with all their so smart they are stupid technology, goes and drains the battery down. As you might see my other comment, I installed a Noco 5 battery tender under the hood and at this point still have the cord routed so I have to lift the hood and then plug it in but am typically parked in a garage or a shed so its not risking the engine hood in the wind. That way I am assured or hopefully so of not finding I have a battery drawn down and can't even start the truck and that also damages the battery to draw it down too far. 
    • I guess no surprise my guesses were wrong !, at least now I know if I ever happen to see it grayed out in my own truck as to what is going on.    I never happened to catch my truck with it grayed out, it seemed every time I would test to see if there was an update it never found anything and yet more than once I would check to see if there was an update and there was nothing, then a day later or even that same morning I would drive to town and after more than one engine shut down in town as I did my errands it would pop up that there is an update now ready to install and the only place I have a connection to the internet is at home by wifi so its not as if it grabbed the download while driving. I don't trust these new vehicles due to all the crap they can decide to do while sitting for some days not running and run the battery down so most of the time if I know the truck will sit for a few days I plug in the battery tender I have mounted under the hood and so the only time the truck must have downloaded software was when it was sitting in the garage where the signal is awful but I have that tender plugged in and somehow it managed to download it. I honestly detest all this crap, way to easy to leave a person stranded.    Since I don't trust any of it I don't do the install of the already downloaded software until I get home and sometimes have even sat in the truck to watch what its doing as its going through the process to its conclusion as its not like it is set up that it will tell you the next time you fire up the engine that the update that was initialed actually installed or installed properly. Yes I can go into the updates and see the list. After I go through the install where I feel its safe to do so in case it breaks down as a result, I will plug in the battery tender after the fact to recharge as I don't know how much power its taking just to do the install and that can take a while for it to install. 
    • Thanks for the reply. All settings were correct and the engine was off, as it was supposed to be. It turned out to be something simple. I took a drive for about an hour. I must have had a low battery without knowing it. The voltage gauge on the display looked ok. At the end of my drive, I shut off the engine and the update prompt came up and it updated normally. It’s ironic because one of the features of the update is a reduction of battery drain. 
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...