Varying Knocking/tapping under my truck

[Sketch414]

Started maybe a month ago, there's a light knocking/tapping sound with a weird uneven rhythm (as in some taps are louder some are softer, not evenly spaced out). It starts after the rpm drop on startup and quiets down after driving a while. It can be heard from the front tire to the back tire, coming from the underside.
I have a 2012 with the 5.7 Hemi and 122k miles. Always maintenanced on time, had the hemi tick from exhaust leak/manifold fixed and fuel injectors cleaned this year. Performance hasn't been affected by this specifically but it's been occasionally sluggish on acceleration since a while before this noise appeared. My mpg got a little worse though.
Hopefully this link works, here's a walk around: https://photos.app.goo.gl/cia8adSn3fKhR86t5

 

[Sketch414]

5.7 Hemi varied tapping?

Around 30 seconds into the video, the rpm drops as normal and a variable tapping arises. I've had the "Hemi tick" exhaust leak fixed, this is a different, fa...

youtu.be

 

[Namgrunt67]

Have you checked your cadaletic (spelling) ? converter , i had that same thing and it was my cad converter, peices breaking loose .
Just a thought
Ron

 

[Sketch414]

I hadn't thought of that! I'll look more into it.

 

[CamperMike]

Does it quiet down again when fully warned up? Mine is quiet when cold, then makes a bit of noise while warming up then is quiet when hot and has done that since I got it and i am not concerned with it. Is the noise noticeable when in the cab or only outside?

 

[ramffml]

This is the exact same sound I'm trying to get rid of in my truck as well. Seems worse in the winter. Is it piston slap maybe?

In my case, that sound pretty much goes away once the truck is hot.

To me it doesn't sound like the classic "hemi tick" that I've heard videos on before, but always hard to tell when comparing sounds from videos.

Maybe @Burla has some thoughts?

 

[ramffml]

Also if you want a bit of piece of mind, try sending a sample of your used oil to Blackstone and have them analyze it. They can tell you if there are high amounts of wear material in your oil. My reports are great so far so the noise we here doesn't necessarily mean the engine is on the way out.

Mine also made that noise from day 1 as far as I can remember (I bought it new).

 

[Sketch414]

Can't hear it in the cab or front, barely hear it in the engine bay and standing next to it, can fully hear it crouching down. It does quiet down after warmup, I drove it on the freeway like 10 minutes and it was almost gone. Mines always been pretty quiet otherwise. It's definitely not the classic tick, had that one before.

 

[Burla]

Hard to tell, the exhaust is so loud I can barely hear it. Sounds like valve spring or sticky lifters.

Have you tried a lubrication strategy? Read this thread poll, the one thing you are facing is the mileage, there is a when not to try a lubrication strategy thread, it is a risk in high mileage engines.

 

[Namgrunt67]

Also if you want a bit of piece of mind, try sending a sample of your used oil to Blackstone and have them analyze it. They can tell you if there are high amounts of wear material in your oil. My reports are great so far so the noise we here doesn't necessarily mean the engine is on the way out.

Mine also made that noise from day 1 as far as I can remember (I bought it new).

I just bought a new 2022 1/2 ton Hemi, when I first start it it makes that noise, I think it is the exhaust pipe rattle until it warms up a bit,then all is quiet again. I have 300 miles on it and I probabley paid extra for that noise,
seems like I paid extra for every thing ,LOL (this will be my last truck @75,I do not think I will need another one.)

 

[JHoward]

Well, OP fwiw of many times I've fueled up my HEMI with non top tier or 87 octane gas I can hear the " light knocking" sound.

Maybe try an top tier quality fuel and see if that helps to resolve your knocking issue?

 

[Burla]

I just bought a new 2022 1/2 ton Hemi, when I first start it it makes that noise, I think it is the exhaust pipe rattle until it warms up a bit,then all is quiet again. I have 300 miles on it and I probabley paid extra for that noise,
seems like I paid extra for every thing ,LOL (this will be my last truck @75,I do not think I will need another one.)

There are two possibilities usually for this which is called hemi tick, exhaust bolts or lifters. Bolts should be fixed by dealer, so should lifters but sometimes they wont fix it. Look up did redline kill my hemi tick, and did lubegard kill my hemi tick and learn about a lubrication strategy and forum results. Also, look at oil filter thread. Syn thread explains why these strategies worked, it is science not brand.

 

[Sketch414]

I just bought a new 2022 1/2 ton Hemi, when I first start it it makes that noise, I think it is the exhaust pipe rattle until it warms up a bit,then all is quiet again. I have 300 miles on it and I probabley paid extra for that noise,
seems like I paid extra for every thing ,LOL (this will be my last truck @75,I do not think I will need another one.

There are two possibilities usually for this which is called hemi tick, exhaust bolts or lifters. Bolts should be fixed by dealer, so should lifters but sometimes they wont fix it. Look up did redline kill my hemi tick, and did lubegard kill my hemi tick and learn about a lubrication strategy and forum results. Also, look at oil filter thread. Syn thread explains why these strategies worked, it is science not brand.

My mechanic suggested Lucas, gotta research as I'm new to all that. I won't take it to the dealer because they're absolutely hopeless around here (so-cal). I'm looking to fix before anything gets worse though. I'd always have a truck (too versatile not to- commute? Race? Road trip? Haul? Sleep? It's got your back) but I'd like to keep this one around a while.

 

[Sketch414]

Well, OP fwiw of many times I've fueled up my HEMI with non top tier or 87 octane gas I can hear the " light knocking" sound.

Maybe try an top tier quality fuel and see if that helps to resolve your knocking issue?

If only gas wasn't $7.... Lol I was thinking about it on my next fill up actually, I've never used anything but 87 in these. I do use top tier brands (earlier on Chevron, nowadays mostly 76, Shell). I used Sinclair for a bit and I hope it didn't hurt something.
I think another thing is these engines like a little abuse because they need the oil splash on the cam.

 

[Atcer2018]

I think another thing is these engines like a little abuse because they need the oil splash on the cam.

Splash lubrication may work for Briggs and Stratton but imma disagree that the 5.7 Hemi is waiting for a little splash of oil under the valve covers. It’s a fairly good size engine mounted in a 6000 pound metal box not a snow globe. Lol

 

[Burla]

My mechanic suggested Lucas, gotta research as I'm new to all that. I won't take it to the dealer because they're absolutely hopeless around here (so-cal). I'm looking to fix before anything gets worse though. I'd always have a truck (too versatile not to- commute? Race? Road trip? Haul? Sleep? It's got your back) but I'd like to keep this one around a while.

Lucas is an oil thickner, it has a viscosity of 110. 5w20 has a viscosity of 9 and 5w30 has a viscosity of 12. There are much better ways to skin that cat then adding lucas.

 

[Burn2k12Ram]

Lucas is an oil thickner, it has a viscosity of 110. 5w20 has a viscosity of 9 and 5w30 has a viscosity of 12. There are much better ways to skin that cat then adding lucas.

Yes in some cases can backfire using lucas due to the high viscosity making it more difficult for the parts to move.

 

[Sketch414]

Splash lubrication may work for Briggs and Stratton but imma disagree that the 5.7 Hemi is waiting for a little splash of oil under the valve covers. It’s a fairly good size engine mounted in a 6000 pound metal box not a snow globe. Lol

Lmao guess YouTube did me wrong there

 

[Sketch414]

Lucas is an oil thickner, it has a viscosity of 110. 5w20 has a viscosity of 9 and 5w30 has a viscosity of 12. There are much better ways to skin that cat then adding lucas.

Would I add redline after I fix things as well? As a preventative for it happening again?

 

[Burla]

Would I add redline after I fix things as well? As a preventative for it happening again?

Redline may actually fix this if it is lifter tick, first you need to find out what the issue is. Sometimes the issue is actually low levels of extreme pressure additives in modern oils in the hemi when you put a higher AW/EP additives in the knock or tick goes away. Metalurgy tests help tp prove this point, see paper below.