Jump to content

Engine knock a 500 miles

bass mechanic
 Share

Recommended Posts

MN6.2 Enthusiast

MN6.2

Posted
Posted
21 hours ago, KB Chevy said:

This is my 5th diesel and none have ever sounded like this with the loud knock, and my 2020 does. I can't believe they changed anything from 2019 to 2020 that would cause this obnoxious knocking sound.

Didn't they have to change the back of the engine to accommodate the new 10 speed transmission? Doesn't seem like enough to create a knock like that but that is one major thing they changed. 

  • Like 1
  • Replies 135
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

bass mechanic
bass mechanic

heres a video with the sounds  

Sask Farmboy
Sask Farmboy

My first chime in for this topic. My 2020 Denali DRW is being built in 2 weeks so I will be checking it out closely. I used to be a Chevy tech and finding stuff like this was my life. I

MN6.2
MN6.2

Didn't they have to change the back of the engine to accommodate the new 10 speed transmission? Doesn't seem like enough to create a knock like that but that is one major thing they changed. 

Posted Images

KB Chevy Enthusiast

KB Chevy

Posted
Posted
1 hour ago, MN6.2 said:

Didn't they have to change the back of the engine to accommodate the new 10 speed transmission? Doesn't seem like enough to create a knock like that but that is one major thing they changed. 

That could be a contributing factor, thank you for the info.

newdude Senior Enthusiast

newdude

Posted
Posted (edited)
On ‎10‎/‎28‎/‎2019 at 11:34 PM, bass mechanic said:

honestly i dont think for as long as this engine has been around this is a problem sound. diesels are noisy! if it was rod knock it would get louder with RPM and likely get worse under load.

and the fact others have the exact same sound, im sure any dealer will tell me its normal. ill wait till something bad happens and have it covered under warranty.

 

I watched your youtube upload and the ones you sent.  The youtube one I heard it most I think.  That deep "da da da da da da da da da da da da" thumping sound I assume is the one?  I went to some 2020's we have but they have zero miles on them and didn't have a similar thumping sound.  I can definitely hear the DEF injector tick in park that hits about every 1-1.5 seconds.   

 

5 hours ago, MN6.2 said:

Didn't they have to change the back of the engine to accommodate the new 10 speed transmission? Doesn't seem like enough to create a knock like that but that is one major thing they changed. 

 

No.  Same rear flywheel housing on the back 2017-2020.  

Edited by newdude
KB Chevy Enthusiast

KB Chevy

Posted
Posted
1 hour ago, newdude said:

 

I watched your youtube upload and the ones you sent.  The youtube one I heard it most I think.  That deep "da da da da da da da da da da da da" thumping sound I assume is the one?  I went to some 2020's we have but they have zero miles on them and didn't have a similar thumping sound.  I can definitely hear the DEF injector tick in park that hits about every 1-1.5 seconds.   

 

 

No.  Same rear flywheel housing on the back 2017-2020.  

Yes it's a deeper thumping sound that is heard. It's harder to get it on an audio file to hear the true sound but it sounds like you can hear it. In person it's very noticeable. Yes i hear the injector tick which you can hear on all diesels and I actually like it. LOL The thumping is obnoxious, I own a RV dealership and my service manager was a Chevrolet service manager for years and worked at the Chevy dealership for over 20 years in different capacities. She stills has connections with the GM reps and has a call into him about it. She's never heard a diesel motor sound like this so not sure what to make of it. The warranty will cover anything that goes wrong but for 77k you would think it wouldn't sound like it does. Also this is my 5 diesel and when i was in the waste business we had 100+ diesel trucks, most large trucks but again I've never heard a diesel sound like this and not have an issue. Thank you for your time, I greatly appreciate your help! Please keep me posted if you should hear any info on this. 

 

Kenny 

  • 2 weeks later...
GPMS New Member

GPMS

Posted
Posted
On 10/28/2019 at 10:09 PM, bass mechanic said:

heres a video with the sounds

 

I have the same thing. it sound like shit when you hear it.

CRApex Enthusiast

CRApex

Posted
Posted

My 2017 had a knock you could hear while slowing to a stop, 2020 does it too.  Knock knock sound then goes away once stopped.  Had no issues with the 2017 

KB Chevy Enthusiast

KB Chevy

Posted
Posted
17 hours ago, GPMS said:

I have the same thing. it sound like shit when you hear it.

Yes that's the exact sound. I had a GM rep come and listen to it and he said that's how they sound now but to confirm it he called a GM engineer who did confirm it. Said the motors are quieter in some aspects now and some sounds like the thumping/knocking are more pronounced. I find it very annoying but not much I can do about it. 

joelabq Enthusiast

joelabq

Posted
Posted

Mine has the same noise. Call me weird, but this sound did not bother me at all and i love how this engine sounds as a whole. I think the deeper noises are much less annoying then the higher pitched of the old. It is subjective though.

jhc2 New Member

jhc2

Posted
Posted

Great video, mine has the same sound. Dealer said it was noise from the egr system and naturally they say it's normal. Hope someone can figure out what it is.

  • 2 weeks later...
  • 2 weeks later...
Turtlern56 Enthusiast

Turtlern56

Posted
Posted

I have a 2020 AT4 HD 400 miles now and mine has made that exact same knock as the video outlines.  I commented to the salesman about it but he said he wasn’t that familiar with any of the sounds.  I had been waiting a month for delivery bc of the GM strike.  I went back to the dealer the same day I took delivery last week and made them start another diesel and it had same knock but not near as loud as mine. Heard three others since with no noise. It’s Horrible at idle and seems to go away about 900-1000 rpms.  Some mornings not audible for a minute or two then comes on strong as it warms. Service manager today says it’s normal and they printed me off the ticking service bulletin. It’s a knock not a tick. He also told me to drive it and about halfway through oil life if still audible then they might investigate it. It’s a little embarrassing I’ve had a couple people ask me “what’s that knocking?”  I give them the $70k shrug and say it’s normal. Lol. I hope they figure something out. Reprogram an injector if it’s like a fuel knock or something.  Found this thread researching and thought I would chime in. 

Anthony Greco Enthusiast

Anthony Greco

Posted
Posted (edited)
On 10/28/2019 at 11:09 PM, bass mechanic said:

heres a video with the sounds

 

Sounds like a loose harmonic balancer.    Have you checked oil pressure with a mechanical gauge?    If it’s a bad or loose crankshaft bearing then oil pressure will be lower than normal.  Just thoughts of what could be.  Hope it’s nothing major.

Edited by Anthony Greco
Add on
jhc2 New Member

jhc2

Posted
Posted

Similar posts on the dieselplace forum so there others with the 2020 duramax with the same problem.  Anyone able to post this video to Banks Power?  Gale seems to be the utmost expert on the duramax.  He tears these engines apart all the time.  If anyone can shed a light on the problem it would be him.

Anthony Greco Enthusiast

Anthony Greco

Posted
Posted
On 12/3/2019 at 5:02 PM, Turtlern56 said:

I have a 2020 AT4 HD 400 miles now and mine has made that exact same knock as the video outlines.  I commented to the salesman about it but he said he wasn’t that familiar with any of the sounds.  I had been waiting a month for delivery bc of the GM strike.  I went back to the dealer the same day I took delivery last week and made them start another diesel and it had same knock but not near as loud as mine. Heard three others since with no noise. It’s Horrible at idle and seems to go away about 900-1000 rpms.  Some mornings not audible for a minute or two then comes on strong as it warms. Service manager today says it’s normal and they printed me off the ticking service bulletin. It’s a knock not a tick. He also told me to drive it and about halfway through oil life if still audible then they might investigate it. It’s a little embarrassing I’ve had a couple people ask me “what’s that knocking?”  I give them the $70k shrug and say it’s normal. Lol. I hope they figure something out. Reprogram an injector if it’s like a fuel knock or something.  Found this thread researching and thought I would chime in. 

Never stops amazing me what dealers try to pass off as normal.   Usually there are one or two Techs on top of these issues.  Those are the ones you want working on your truck.

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
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,947
    Total Members
    8,960
    Most Online
    Sothpaw27
    Newest Member
    Sothpaw27
    Joined

  • Who's Online   2 Members, 0 Anonymous, 413 Guests (See full list)

  • Latest Articles

  • Posts

    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      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.
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      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.         
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      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. 
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      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. 
    • nfisherman
      Software Update

      By nfisherman · Posted

      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...