Rough Cold Start - What's That Noise?

[OffTheAir]

Hello, everyone! Hope you're all doing well and excited for the Holiday season.

I'm very sorry for yet another "what's that noise?" thread, tried to shuffle through the Troubleshooting section to pinpoint exactly what it is I'm hearing, but was unsuccessful. 

Just as luck should have it I found this video on YouTube that is the EXACT engine noise I'm experiencing:

https://www.youtube.com/watch?v=EZAj8y7xm9s

I've been more concerned with how rough the engine sounds right at startup, but the other day I did also get the exact "chattering" noise that is present in this video (albeit for a quick second, it sounded like acorns falling through the engine bay).

It's been a little chilly in Michigan the past couple weeks, so obviously I expect startup to be a little tougher on the ol' 5.3. However, I do not recall it ever sounding like this, unless maybe I'm just more paranoid than ever (if that's even possible)? Fortunately, it does idle normal within a couple seconds of just warming up, and I really don't see any change in the drivability whatsoever, no check engine light, etc. 

While I hope to be able to identify what exactly this is, the answer I'm really hoping to gain with this thread is: should I be worried? I love this truck, it's been reliable and dependable over its 7+ years in our family, I really, really have no desire to get rid of it. I worry because a big repair right now would really, really suck. My main concern is if I'm really jacking something up  by doing my morning commute every morning when there could be something wrong that I don't know about.

Very sorry to ramble, hope you all can help me out! Again, thank you so much for taking the time to check this out.

[Supreme Pizza]

Play this video from 2:50 to 2:53.

 

It may help to settle your rage.

 

 

 

 

[newdude]

If its the same as in that video, sounds like an exhaust leak?  Possibly broken manifold bolts.  Pop the hood and check them out if you can see them.  Any bolt heads broken, stands a chance you need new bolts and gaskets.  

[Supreme Pizza]

I would re-program the computer ($50) or use an OBD2 AFM disabler ($100), and then I would do a motor flush using "motor medic". After that, change the oil every 3,000 miles religiously.

 

If that doesn't solve the problem, pull the valve covers to see which rocker has slack. Then pull a head, and drop in a new lifter. Not all of them, just one. The whole job takes a day and costs $100. If you don't have the tools or a manual, the whole job will take a day and maybe $220.

[Supreme Pizza]

5 minutes ago, newdude said:

If its the same as in that video, sounds like an exhaust leak?  Possibly broken manifold bolts.  Pop the hood and check them out if you can see them.  Any bolt heads broken, stands a chance you need new bolts and gaskets.  

 

 

Absolutely. It could be an exhaust leak. I would expect a CEL if that was the case, but maybe not. My 2003 had a busted manifold bolt and I was getting a bank 1 catalyst below threshold code.  I easy-outed the bolt and threw another one in. Even with thread-locker, I have to re-tighten that same bolt twice per year, otherwise I get a tick and a code.

[OffTheAir]

1 minute ago, newdude said:

If its the same as in that video, sounds like an exhaust leak?  Possibly broken manifold bolts.  Pop the hood and check them out if you can see them.  Any bolt heads broken, stands a chance you need new bolts and gaskets.  

I am so glad you mentioned this, completely slipped my mind! I will absolutely check this out and report back. Thank you so much! 
Definitely could be a possibility. I remember reading about this problem last year when I was diagnosing my failed radiator/water pump.
 

2 minutes ago, Supreme Pizza said:

I would re-program the computer ($50) or use an OBD2 AFM disabler ($100), and then I would do a motor flush using "motor medic". After that, change the oil every 3,000 miles religiously.

 

If that doesn't solve the problem, pull the valve covers to see which rocker has slack. Then pull a head, and drop in a new lifter. Not all of them, just one. The whole job takes a day and costs $100. If you don't have the tools or a manual, the whole job will take a day and maybe $220.

Appreciate your response, Supreme Pizza, thanks a lot! Got some time off and will definitely look into troubleshooting the motor. Been very religious with my oil changes, curious to see if flushing the motor will help. Will take what you said to heart, not sure how involved I want to get (will find out when I see what's wrong), but if it's the required preventative maintenance and will save me some nasty repair bills, I'm all for it. 

[OffTheAir]

Hey all,

Just wanted to post an update/resolution to this thread for those who view it in the future and have the same noise at cold start.

Newdude and Supreme Pizza are correct, it was an exhaust leak. I had three broken exhaust manifold bolts on the passenger side. Replaced with new bolts and gasket and the problem was solved. 
 

Edited December 28, 2021 by OffTheAir

[Supreme Pizza]

3 hours ago, OffTheAir said:

Hey all,

Just wanted to post an update/resolution to this thread for those who view it in the future and have the same noise at cold start.

Newdude and Supreme Pizza are correct, it was an exhaust leak. I had three broken exhaust manifold bolts on the passenger side. Replaced with new bolts and gasket and the problem was solved. 
 

 

 

 

Thanks for the update.

 

I'm glad to hear that it all worked out well for you.