04 Denali rattle can sound around 800-1200 rpms

[DenaliJJ]

I will contact blackstone. Might need to wait till next change because it's in a container with the 302s oil now. Anyone else want to go with piston slap? I would be totally with the noise if all it was piston slap haha. I have great oil pressure now runs good and no codes in the system.

 

[HiHoeSilver]

My thoughts too. Funny thing is I can't hear it when someone revs it up past 1200 though. You would think somethin motor related would be louder through Rpms right? What's the easiest way to check the flexplate?

You can see it through the inspection window, just pop the cover off and look in there with a good flashlight.

 

[DenaliJJ]

You can see it through the inspection window, just pop the cover off and look in there with a good flashlight.

Thank you for the reply. What will I be looking for exactly?

 

[HiHoeSilver]

Cracks or missing teeth, etc. You may need to turn the engine over with a big ratchet to spin it around as you can only see so much through the inspection hole.

 

[DenaliJJ]

Sounds good. Thanks Does this sound like a piston slap lifter or flywheel noise to you?

 

[HiHoeSilver]

So hard to say from videos. Have you tried a stethoscope at all?

 

[DenaliJJ]

So hard to say from videos. Have you tried a stethoscope at all?

Will poke around with a scope today. My neighbor is a gm mechanic at our local dealer and he said it sounds like lifter as his does the same sound and his been doing it for around 70k. Also told me if it backfires then that's not good and pulling the heads and intake is in order to fix it. Book calls for about 8 hours but said could realistically be done in about half that

 

[DenaliJJ]

Figure I'll give an update on the matter. Today I took it out for a spin and since I've never really hammered on it I decided what the hell amd so I took it to about 50 at wot. Oil pressure hit a tad over 60psi and I continued to the gas station. let it sit at home for a few hours and started it up and the noise barely lasts 30secs now and isn't nearly as loud. Maybe the wot cleared some gunk up??

 

[recycleoldgrowth]

My last two suburbans sound just lake that, to me it's good old piston slap. Sounds like crap but clears up quick and I've been told by many sources that it doesn't harm the motor (I personally have a hard time believing that but my first suburban I sold at 300k and was running like a champ)

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[DenaliJJ]

My last two suburbans sound just lake that, to me it's good old piston slap. Sounds like crap but clears up quick and I've been told by many sources that it doesn't harm the motor (I personally have a hard time believing that but my first suburban I sold at 300k and was running like a champ)

Sent from my SM-G530T using Tapatalk

I'm hoping that's all it's. Motor runs great and other than the embarrassing sound at start up I love it. Always been a Ford guy but now I'm lookin at a newer Yukon for the wife and kids