Engine noise heard in cabin from footwell, exhaust leak? normal?

[Kidrcrh]

To start, shortly after I bought my truck I had to bring it back for work that had to do exhaust. I assume they checked extensively for exhaust leaks and other things while they were searching for the issue(10 days), but anyways. The issue is around the exhaust.

 

Sometimes while driving i hear what sounds like an exhaust leak. I dont recall ever hearing the actual engine in the cab before my ordeal. I could hear the tailpipe sounds when merging onto the freeway and accelerating, however i hear ticks around the footwell and im not sure it if is normal. I know what the direct injection ticking sounds like, and it doesnt sound like that. Does anyone else hear the engine/exhaust while just cruising in the cabin?

 

 

Before taking my truck in i had only driven it 400 miles, so i really dont have enough experience to answer my own question.

 

truck is a 2016 Silverado LT 5.3, everything is stock.

[Sierra 5.3]

Mine is the same way. I have read about this and others experiencing the same thing so I just assume it is normal. If you find something though, let us know.

[crushNchowda]

I have noticed the same thing but only after I installed a Gibson catback, sounds very similar to what you hear in the cabin after adding LT headers, only fainter.

 

I don't see any evidence of actual leak & mainly hear it under very light throttle

[Kidrcrh]

I have noticed the same thing but only after I installed a Gibson catback, sounds very similar to what you hear in the cabin after adding LT headers, only fainter.

 

I don't see any evidence of actual leak & mainly hear it under very light throttle

 

I am dead set on it being some kind of exhaust leak. Doesn't do it at idle, only does it while cruising on the freeway and adding certain amount of power. Too little power and there is no issue, too much power and it down shifts and you cant hear it.

 

Fuel pumps run constantly so they wouldn't change with rpm. Lifter noise often doesn't get worse with load, but gets worse when unloaded(decel). I have a friend with a 9 gas analyzer and i have the resources to NDT(non-destructive test) any components i remove. I bet there is a tiny crack somewhere(only expands when hot), or a loose component.

[qwank]

maybe a grommet in the firewall is out of place?

 

also, check the clamp that hold the exhaust to the Y pipe, there's a bulletin about them being installed incorrectly and leaking. you would see black soot around it if it was.

[Sikk50]

I hear the same thing. Though as I think about it, I've never noticed it in v8 only v4. Maybe some relation. But you're right in that it sounds exactly like an exhaust leak. If it was an exhaust leak you'd hear it all the time, primarily when under hard acceleration. Idk about yours, but for mine that's not the case

[Zachlovesfood]

You could get under the truck while someone revs the truck up til you hear it/find it. Done that a few time with new exhaust setups. Easier to hear a leak from down there.

 

 

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[ct_corey]

mine does it with low throttle input, can hear it pretty loud around 50-70mph. sounds like a manifold leak. Been to the dealer 3 times for it. Most the older techs that do diag work cant hear it but every time I have a younger guy go on a test drive they hear it right away. I was loud enough for my cell phone to record it. Im just going to drive it for now because the dealer has no solution for it.

[Thomcat]

Check out the mid joint pipe to pipe connection to see if it is one of the affected vehicles

 

http://sandyblogs.com/techlink/?p=7001

[phabejhmoob]

Mine is the same way. I have read about this and others experiencing the same thing so I just assume it is normal. If you find something though, let us know.

 

I noticed this on mine too at times, when I took my car in for oil service, they noticed it but quickly ruled out that the sound is normal. Direct fuel injection. Although I don't like it, it's not causing any problems.

[scannylada]

Glad to have found this post. This sound has been driving me crazy. I have been driving around with the radio turned down asking everybody who drives with me if they can hear it.

 

I have a 2017 sierra cc short box 6.2L. My truck started to have a transmission issue the driving over rumble strip feeling at the same time as described above ( v4 mode trying to maintain speed ) around 400 mi. At 3000 mi it started to get really bad. I also had the gm borla exhaust with flapper valve installed 3400mi. Took truck to dealer and they did the transmission flush 3 times per the tech bulletin. Got truck back and now the ticking. 4000 mi. on it.

 

First I thought it was exhaust leak. No evidence of that. Thought maybe the dealer put 87 gas in it since they put 250 miles on it trying to replicate issue and then making sure they fixed it and it was engine knock. I am on my second tank of 93. Have thought maybe at times it sounds like it could be a rapid fluid moving sound from the transmission. Have thought about it being the flapper valve for the exhaust. In v4 mode it is closed. In v8 mode it is open. Sound seams like it happens when pressure build in v4 mode and the flapper might be tarting to open (spring loaded).

[madsen203]

Found a fix for this. It's been months since I brought it home. It has been since day one after a few hundred miles that this noise has been there. Finally climbed under the truck to look. Then I lifted the carpet. 

 

I found there is a wire (not sure yet what it goes to) that enters from under the carpet below the left rug mount towards the seat. I first moved the wire so it was routed differently because it was causing a lump under the mat that was uncomfortable. I then put a piece of DynaMat over this to seal the grommet and wrapped the wire so there was no "air gap" to allow sound to penetrate. 

 

The sound has dropped dramatically. It is still very faint. I found the ticking is from the DI or valve train that reverberates down under the truck past the transmission/transfer case. The sound would then come through this grommet and enter the cabin. Now that there is dynamat over this, the sound is no longer as loud (hardly notable). I only had a tiny piece of dynamat so I will order a few square feet of off-brand to put a few layers on top and one under the truck. That should eliminate ALL of the ticking sounds. 

 

I am stoked! The truck finally feels "new" again. 

[ShubiSnax]

14 hours ago, madsen203 said:

Found a fix for this. It's been months since I brought it home. It has been since day one after a few hundred miles that this noise has been there. Finally climbed under the truck to look. Then I lifted the carpet. 

 

I found there is a wire (not sure yet what it goes to) that enters from under the carpet below the left rug mount towards the seat. I first moved the wire so it was routed differently because it was causing a lump under the mat that was uncomfortable. I then put a piece of DynaMat over this to seal the grommet and wrapped the wire so there was no "air gap" to allow sound to penetrate. 

 

The sound has dropped dramatically. It is still very faint. I found the ticking is from the DI or valve train that reverberates down under the truck past the transmission/transfer case. The sound would then come through this grommet and enter the cabin. Now that there is dynamat over this, the sound is no longer as loud (hardly notable). I only had a tiny piece of dynamat so I will order a few square feet of off-brand to put a few layers on top and one under the truck. That should eliminate ALL of the ticking sounds. 

 

I am stoked! The truck finally feels "new" again. 

Nice fix! I noticed the sound years ago but have come to live with it as it's not bad at all and can only hear it when the radio and hvac are off and I'm in v4 mode feathering the gas pedal.

I too thought it was an exhaust leak in the front at first. Funny thing, I just recently installed a power lock for my tailgate and ran the wires up through that same opening under the driver-side carpet.

Guess I'll be going back in there to throw in some Dynamat. Thanks for posting!