Jump to content

Are the 6.6 l8t engines inherently noisy?

DuckBoi

By DuckBoi
in 6.6L Gas V8 (L8T)

 Share

Recommended Posts

chris21 Enthusiast

chris21

Posted
Posted
On 5/16/2024 at 10:52 AM, UWSkier said:

I'm wondering if mine is chirping from the same area.  I started the truck with the hood open yesterday and it actually sounds like the sound is coming from underneath and towards the rear of the engine compartment.

Did you ever find the source of the chirp under light acceleration? I am having a similar sound in my 2025 2500 with 3000 miles, with light acceleration between 30-40 mph and only when the engine has a little bit of load. I thought it was coming from the rear end, dealer said they didn't hear it, then after a second drive they said it was my truck cap whistling... but it is a chirp that clearly only happens under light engine load. I added fluid to the rear diff as it was a bit over half a quart low (same dealer said level was fine,  took over a half quart to bring it up to 1/2" below the fill threads) it still made the noise after that.

  • Replies 48
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

DuckBoi
DuckBoi

Dealer has truck. Will update this thread when i hear back. 

Jettech1
Jettech1

I don't know about others but mine is quiet and silky smooth.

DuckBoi
DuckBoi

Confirmed engine is misfiring, maybe on two cylinders, continuous misfires not intermittent.  All three cats glow purple/red hot after short distance drives like 10 min drives maybe and just from idli

Posted Images

GMCustomerService Senior Enthusiast

GMCustomerService

Posted
Posted
On 5/10/2025 at 11:29 AM, chris21 said:

Did you ever find the source of the chirp under light acceleration? I am having a similar sound in my 2025 2500 with 3000 miles, with light acceleration between 30-40 mph and only when the engine has a little bit of load. I thought it was coming from the rear end, dealer said they didn't hear it, then after a second drive they said it was my truck cap whistling... but it is a chirp that clearly only happens under light engine load. I added fluid to the rear diff as it was a bit over half a quart low (same dealer said level was fine,  took over a half quart to bring it up to 1/2" below the fill threads) it still made the noise after that.

Unexpected concerns with such a new vehicle are understandably upsetting, and we would like to learn more. Please email our team at [email protected]. We look forward to learning more. By sending us a message, you consent to the information you provide being monitored and recorded by GM or those acting on GM’s behalf, subject to the GM Privacy Statement: https://www.gm.com/privacy-statement.

UWSkier Enthusiast

UWSkier

Posted
Posted
On 5/10/2025 at 9:29 AM, chris21 said:

Did you ever find the source of the chirp under light acceleration? I am having a similar sound in my 2025 2500 with 3000 miles, with light acceleration between 30-40 mph and only when the engine has a little bit of load. I thought it was coming from the rear end, dealer said they didn't hear it, then after a second drive they said it was my truck cap whistling... but it is a chirp that clearly only happens under light engine load. I added fluid to the rear diff as it was a bit over half a quart low (same dealer said level was fine,  took over a half quart to bring it up to 1/2" below the fill threads) it still made the noise after that.

nope.  Still doing it at 20k miles.  Not getting any worse.

AT4X Steve Enthusiast

AT4X Steve

Posted
Posted
On 5/12/2025 at 6:14 PM, UWSkier said:

nope.  Still doing it at 20k miles.  Not getting any worse.

Mine has the same noises as you have described...slight chirp and the normal fuel injection tick.   Dealer has looked at it twice and said it is not an issue and is normal.   It is not getting worse just annoying for a new truck.  Otherwise I love the 6.6gas

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

  • Latest Articles

  • Posts

    • Tyler Gibbs
      Travel Trailer 2024 2500 HD 6.6 Gas Engine ?

      By Tyler Gibbs · Posted

      The curb weight on a 1 ton crew cab long bed is around 7k lbs.  Now, I don't know where you went to school but 9k is not more than 2x 7k lbs. More than 2x 7k lbs would be 14k+.   With that said, obviously yes you're going to feel a 9k lb trailer when slowing down.  I already said, when accelerating.  When changing lanes?  No.  But if you look at the context of what was quoted, the original person said, "after a mile or two..." which means that would be after the accelerating portion and you're driving a generally steady pace.  Please do learn to read and comprehend.
    • sFrank
      2026 Silverado Range AFM DFM ECU loaction

      By sFrank · Posted

      So I purchased the Range unit for my 2026 and I am seeing different locations suggested for the ECM . Can anyone confirm wither under hood, left side or right side or behind the wheelwell?
    • No F-bdy Bs
      Dave's Auto (custom engine builder) tear down of L8T

      By No F-bdy Bs · Posted

      Like I've said before. Di and Carbon buildup is not that big of a concern. Engine had minimal buildup, and that engine was obviously not super well maintained. Do regular oil changes, and you're gtg as long as the rest of the truck lasts. Also, the High Pressure FP that people ****** about, but can't tell you why.  Now, I wish they'd trash the variable oil pump. No real world issues with them, but I'll gladly eat whatever miniscule MPG it's saving me in favor of more oil at all RPMs.    Curious to see his assessment of the 7.3 compared to the 6.6. I expect he'll praise the port inj, but from a structural standpoint, the 6.6 is as robust as any engine out there.    Not to take away from the 7.3. I feel it's equally as good as the 6.6.     As to heat on the rear cyls, I'd have to see numerous examples before I'd say it's an issue. Especially not knowing the history of that engine. For all is known, they could have blown a rad hose, and ran it hot, and the 2 rear cyls may be the first to get hot in a low coolant situation, but not be an issue aside from that. 
    • Donstar
      Navigating senior years.

      By Donstar · Posted

      "Life is getting back to normal."    I'm driving again and all new joints are operating as expected for this stage of recovery.   My most recent joint replacement still requires a lot of attention but experience has taught me that time will quiet the remaining pain.  I joked with my surgeon that another joint replacement would take my mind off my most recent surgery and he responded by saying the next will be a hip!  There are no plans for another surgery but, unlike me, I don't think he was joking!  I certainly wouldn't refuse further replacement  if required but hope to spend time out of the "post-op"  period.  I can't stress enough that if you have been recommended for total hip, knee or shoulder replacement that you welcome the offer.  Post-op "recovery" may sound daunting and painful, however, this is far better than the insidious erosion of mobility you are currently experiencing.  Imagine what it would feel like to wake up most mornings feeling better and more mobile than you did the previous day!  Prior to my first surgery in June 2025, even getting out of bed was becoming a formidable task.  Since the day after my first surgery, I get out of bed everyday easily and unassisted.  Making the switch to feeling a little better each day rather than a little worse, is hugely motivating!
    • Coastie05
      ‘25 Silverado purchase- back to dealership for bumper/radio issue

      By Coastie05 · Posted

      Hope it all works out for you. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...