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Is this sound normal

2229 Views 16 Replies 11 Participants Last post by  Rockster
Hey guys just recently got rid of my srt jeep for a hellcat. Brought a used 2020 with crazy low miles. I think it’s making a weird sound at idle and wanted to know if this was normal. I looked at all the bearings noise video and mines sounds different. Any help would be greatly appreciated. Thanks

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2020 Challenger Hellcat Redeye Wide Body
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I dont recall my ‘20 sounding like that. I’m going to go take a listen.
 

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2019 Challenger Hellcat Widebody (destroyer grey)
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That doesn't sound like anything with the engine, more of like something is rattling. Maybe a bad engine mount or some accessory making contact with the engine somewhere? Sounds like something with mass as well, a solid sounding rattle.
 

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Hey guys just recently got rid of my srt jeep for a hellcat. Brought a used 2020 with crazy low miles. I think it’s making a weird sound at idle and wanted to know if this was normal. I looked at all the bearings noise video and mines sounds different. Any help would be greatly appreciated. Thanks

No, not normal. Sounds like the SC Impellers are hitting. Could be caused by a bad bearing(s).

Might be some idler pulleys as well. It's some rotating member.

Suggest taking a 12" screwdriver and use it as a stethoscope (or use an actual technician's stethoscope). Touch the blade end on the supercharger housing and the handle end touching your ear and listen (not a joke). Then, there's the drive ends where the bearings are mounted. If it's coming from the SC, it will be very obvious using a stethoscope and listening to various points on the SC, especially near the drive end.

If you do this, be very, very careful while the engine is idling. If you are not comfortable doing this, then get a Dodge SRT Tech to do it.

Let us know...

Best!
 

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Discussion Starter · #6 ·
If the bearings
No, not normal. Sounds like the SC Impellers are hitting. Could be caused by a bad bearing(s).

Might be some idler pulleys as well. It some rotating member.

Suggest taking a 12" screwdriver and use it as a stethoscope (or use an actual technician's stethoscope). Touch the blade end on the supercharger housing and the handle end touching your ear and listen (not a joke). Then, there's the drive ends where the bearings are mounted. If it's coming from the SC, it will be very obvious using a stethoscope and listening to various points on the SC, especially near the drive end.

If you do this, be very, very careful while the engine is idling. If you are not comfortable doing this, then get a Dodge SRT Tech to do it.

Let us know...

Best!
it seems to go away if your not idling. To me it sounds like a bad pulley or something. I’m hoping it’s a quick fix. Just brought the car.
 

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2020 Challenger Hellraisin Scat Pack.
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My WAG is something with the accessory drive is making the noise.

I like the idea of using a stethoscope to try to pinpoint the source of the noise. Knowing where the noise is coming from is almost as good as knowing from what it is coming from...

If you do this and find the noise appears to be coming from the supercharger then the bearings or something is suspect. The noise doesn't sound like any supercharger bearing noise, good or bad, I've heard but it could still be at the supercharger.

Or if the noise is present from a cold start you can remove the accessory drive belt -- note carefully its routing and direction the belt rotates to install it back exactly the way it was on to begin with -- then start the engine and let it run only long enough to confirm the noise is gone or still present with the accessory belt removed.

If the noise is gone while you have the belt off check all accessory drives for excessive play. My experience with other cars over the years is any play is a sign the drive is bad. The rest of the drives had no discernible bearing play.

Check idler and tensioner rollers for any bearing play. Besides the occasional noisy water pump I have had one car with two idler roller bearing "failures" separated by years and tens of thousands of miles.

Also, a sign an accessory drive might be bad is if the edge of the belt is worn. The sides/edges of a serpentine belt should not touch the sides of the accessory drive pulleys.
 

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Definitely doesn't sound right, get it to the dealer asap. It's under warranty so that shouldn't be an issue unless your not happy with your local dealer.
 

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Nope that’s not right at all, something is for sure off. A wooden dowel rod or broom stick works great to use as a stethoscope to pinpoint the sounds root cause
 

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If the bearings

it seems to go away if your not idling. To me it sounds like a bad pulley or something. I’m hoping it’s a quick fix. Just brought the car.
It may go away off idle, but does not mean it's okay. You have a noise AT idle that is not normal and several here have concurred. Something is hitting something and my stethoscope suggestion may help you dial in on the issue. FWIW, I would no accept your noise; it's abnormal. If it's not a bad SC Belt or the serpentine belt or a pulley or dirt on a pulley or some other rotating member, then you should take a hard look at the SC itself.

Suggest your top priority is to either identify or eliminate the SC. The last thing you or Dodge wants is for the SC to explode on top of the motor and then destroy the motor. Motors are $20K & SCs are around $4K

Let us know....
 

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Discussion Starter · #14 ·
Thanks for all the help. I’ve search all over the web and forums and couldn’t find a sound similar to it. I took it to the dealership to have them look it.

It may go away off idle, but does not mean it's okay. You have a noise AT idle that is not normal and several here have concurred. Something is hitting something and my stethoscope suggestion may help you dial in on the issue. FWIW, I would no accept your noise; it's abnormal. If it's not a bad SC Belt or the serpentine belt or a pulley or dirt on a pulley or some other rotating member, then you should take a hard look at the SC itself.

Suggest your top priority is to either identify or eliminate the SC. The last thing you or Dodge wants is for the SC to explode on top of the motor and then destroy the motor. Motors are $20K & SCs are around $4K

Let us know....
 

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It is a repeating sound or resonating, regardless it is a cycle. You can start with the stethoscope. It could be a bad belt, bent pulley, or bad anything on the belt. It is very obvious so it should not be hard to find.

But since it is under warranty, bring it in and let the serv mgr hear it and let him take it from there.
 

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It’s at the dealership now and I will definitely let you guys know what caused the sound. Through all my research I couldn’t find another hellcat replicating the sound of me making.
That's the best course to take. While you can take steps to diagnose this on your driveway why bother? Just you knowing what the noise might be from is not going to make the noise go away.

Well, there are exceptions... I heard a thumping noise from my Hellcat. The noise was in sync with road speed not engine speed. Stopped and looked around the car and didn't see anything. Took off and again the thumping was there. After a few minutes I was at home and I pulled over and looked and spotted some strip of I guess road tar had partially bonded to the tire inside a tread groove. There was enough of a loose end though to smack the car wheel well and make the thumping noise.

But being able to identify the source of the noise and fix it was the exception that proves the rule. Over the years various vehicles have made noises of one kind or another. Almost every time I rely upon a tech to make a diagnosis and address the noise. 'course, in some case not until after -- for curiosity's sake -- I do some investigation on my own and believe I have determined the source of the noise.
 
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