V4 to V8 'Squeak'

[Axxess]

I have the same squeaking sounds on my 16 Silverado. It's due to the exhaust valve closing improperly and forcing exhaust back into the muffler and out thru the drain hole in the exhaust. The dealer has replaced my exhaust once already and that has not fixed the issue. They tell me there is nothing they can do because it's a design issue. This is all after 75% of the truck had to be repainted due to factory paint imperfections. Traded my '14 for this '16 big mistake so far.

[tenthousanddays]

Thanks all for the feedback. Since it's just the flapper I'll just live with it. Not really worth my time to sit in the dealership for 2 hours for something so trivial.

[Dale_K]

After reading the post above that mentioned how the squeak starts with a puff of exhaust out the muffler drain hole I tried a little experiment to plug up the drain hole. I wanted something that I could reverse and remove and wouldn't leave a trace in case I want to try and get a warranty fix.

 

I took some stranded copper wire and after stripping off the insulation I stuffed about 3 individual strands up inside the drain hole. I sort of bent it in a way that it wouldn't fall out. It made a difference. It doesn't squeak during light throttle when the truck goes into V8 mode but I still hear a little squeak when the throttle tip in is more aggressive.

 

So the jury is still out on this. I'm going to put some high temp silicone seal in the drain if the dealer balks at a warranty fix. I'm scheduled to go in for my first oil change in about a month so I'll update this thread with more info later.

[Axxess]

After reading the post above that mentioned how the squeak starts with a puff of exhaust out the muffler drain hole I tried a little experiment to plug up the drain hole. I wanted something that I could reverse and remove and wouldn't leave a trace in case I want to try and get a warranty fix.

 

I took some stranded copper wire and after stripping off the insulation I stuffed about 3 individual strands up inside the drain hole. I sort of bent it in a way that it wouldn't fall out. It made a difference. It doesn't squeak during light throttle when the truck goes into V8 mode but I still hear a little squeak when the throttle tip in is more aggressive.

 

So the jury is still out on this. I'm going to put some high temp silicone seal in the drain if the dealer balks at a warranty fix. I'm scheduled to go in for my first oil change in about a month so I'll update this thread with more info later.

[Axxess]

After reading the post above that mentioned how the squeak starts with a puff of exhaust out the muffler drain hole I tried a little experiment to plug up the drain hole. I wanted something that I could reverse and remove and wouldn't leave a trace in case I want to try and get a warranty fix.

 

I took some stranded copper wire and after stripping off the insulation I stuffed about 3 individual strands up inside the drain hole. I sort of bent it in a way that it wouldn't fall out. It made a difference. It doesn't squeak during light throttle when the truck goes into V8 mode but I still hear a little squeak when the throttle tip in is more aggressive.

 

So the jury is still out on this. I'm going to put some high temp silicone seal in the drain if the dealer balks at a warranty fix. I'm scheduled to go in for my first oil change in about a month so I'll update this thread with more info later.

Dale_K

My exhaust was replace once already under warranty. The new one has the same issue. The dealer should replace yours as well. I did notice that the loaners I was given did not have this issue. Both were '16 Silverados.

[wtchevy15]

Had the same thing. My truck would squeal/chirp when it was in v4. Sound was completely random but would normally occur at lower rpm and would stop once back in v8. I recorded the sound and sent the clip to the dealership and they said it sounded like water in the exhaust???? I don't think so. At that point I already had the adapter valve pinned open which did not make a difference. I decided to replace the exhaust with aftermarket cat back and not go to the dealership every week just to hear they could not replicate the issue. The new exhaust solved the problem.

[WPB]

I have a 2015 model and noticed it this year 2020.  Took a while to determine it was when the engine shifted from v4 to v8.  Has anyone found a solution other than the flapper valve and does it work permanently?

 

[Jonty711]

2 hours ago, WPB said:

I have a 2015 model and noticed it this year 2020.  Took a while to determine it was when the engine shifted from v4 to v8.  Has anyone found a solution other than the flapper valve and does it work permanently?

 

Wire open the valve permanently