392 squeaks after every start

cook03tj

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We got our 392 in May and after every start is squeaks. the squeak goes away after a few seconds depending on the last time it was driven, it squeaks the longest on a cold start. I have taken it into the dealership twice and they are telling me now it is a known issue that is designed to happen. They say it has to do with the performance exhaust letting out pressure at the valve, they said its supposed to do that. I don't believe its supposed to make that noise. Does anyone else have this noise?
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SSWIM

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Mine does the same thing. Almost sounds like a belt noise. Is definitely underneath though. Exhaust noise (leak\whistle) is what I come up with also. Not going to waste the time taking it to dealer though. Having way too much fun with it. I am sure you also found that if revved up it goes away quickly. Was a little concerned at first, yea it is a little annoying, but then said heck with it. LOL

Sam
 
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cook03tj

cook03tj

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Mine does the same thing. Almost sounds like a belt noise. Is definitely underneath though. Exhaust noise (leak\whistle) is what I come up with also. Not going to waste the time taking it to dealer though. Having way too much fun with it. I am sure you also found that if revved up it goes away quickly. Was a little concerned at first, yea it is a little annoying, but then said heck with it. LOL

Sam
At least I'm not the only one! A belt noise is exactly what I thought it was too at first. Thank you!
 

SSWIM

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I have to admit it took a while to come up with that conclusion though. No, it really should not make the noise, but it is not hurting anything at all.


Sam
 

Outrun

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Anyone have video of the sound?
 

SSWIM

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I don't. Just imagine a very erratic belt squeal. Sounds just like that. There are days mine does not even do it. Other days worse than others. No real rhyme or reason, except much more prevalent when first started. Always goes away after a short bit.

Sam
 

Outrun

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I don't. Just imagine a very erratic belt squeal. Sounds just like that. There are days mine does not even do it. Other days worse than others. No real rhyme or reason, except much more prevalent when first started. Always goes away after a short bit.

Sam
Interesting. And the valve is vacuum actuated?
 

Monster1926

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I had a focus RS and the valves would move back-and-forth to knock the carbon off so they didn’t get stuck. It might be what your hearing. Post a video if you can?
 

Jeepmarkjl

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That squeek means your McCluckens diffusion valves are already shot which means then the Schmerkler stems will eventually explode catastrophically. This essentially means the JEEP is a total loss and these items are not covered under warranty. So instead of a total loss I’d be willing to take the Jeep off your hands for $2-3K. It’s a win win. Kinda Sorta.
 

Higgs Boson

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The mopar v8 cold start squeak is actually common across the 392s and hellcat engines. I have a TRX and all the guys complain about the same noise.

jeep dealers all call it normal and due to the manifold design. cold start changes the cam and spark timing so i have a feeling it has to do with combustion events occuring late to help warm the cats up combined with the way the exhaust manifold is apparently designed creating this anomaly.

I wonder if headers eliminate this sound.
 

WIJLU

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It's even listed as a know issue in the small "392 specific" owners manual.
 

SSWIM

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It's even listed as a know issue in the small "392 specific" owners manual.

Really? Do tell. I just looked through the 392 supplement and did not see a thing. Only thing said about any distinct exhaust sound was when under "torque reserve". This is not the "tick" that is addressed either.


Sam
 

WIJLU

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The "tick" at start up is what I was referencing...and what I hear on mine.
 
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