[trippytro]

https://youtu.be/FcaRa2FZ4_8

Just ordered some new mods and....car starts making funny noises the next day, aint life wonderful?


So to clarify, i have high flow cats , midpipes, and exhaust going all the way back. On startup i hear this great screeching almost metallic like sounds. Also happens at idle when modulating light throttle, and sometimes cruising at low speed.

At first it sounded like a belt/tensioner noise. After popping the hood and starting up, i can hear a peep from the belt. The noise is localized to my catylitic/transmission area right under the drive seat when i open the door.

So my guesses are:


-Starter motor? OEM 85K miles?

-Belt and/or tensioner and im just crazy?

-My high flow cats are shot and rattling? They are solo cats i bought used. Maybe 5 years old when i bought them and i put another 2 years?


Im going to pull the belt off this weekend and try to diagnose the tensioners, if thats not it ill try a muffler shop next. Any and all ideas on how to diagnose/find the problem is appreciated,


Thanks guys

 

[ChallyTatum]

Considering you have a 2016 RT we can rule out AES. I would lean towards the cats (tap the pipes with a rubber mallet when cold), then maybe loose clamp?

Starter is plausible but I can hear the typical spin down whine.

BTW I noticed you also have an M6...have you though about maybe the throwout bearing on the trans is going?

 

[trippytro]

Considering you have a 2016 RT we can rule out AES. I would lean towards the cats (tap the pipes with a rubber mallet when cold), then maybe loose clamp?

Starter is plausible but I can hear the typical spin down whine.

BTW I noticed you also have an M6...have you though about maybe the throwout bearing on the trans is going?

Exhaust clamps are tight I didn’t hit the cats when i just had her up.

Did you mean you “can’t” hear the typical spin down or can?

Thought about the trans but....i have no loss in driveability. Was planning in the clutch and synchros at 100K...wish there was a way to narrow it down. Maybe muffler shop is a good first step

 

[ChallyTatum]

Exhaust clamps are tight I didn’t hit the cats when i just had her up.

Did you mean you “can’t” hear the typical spin down or can?

Thought about the trans but....i have no loss in driveability. Was planning in the clutch and synchros at 100K...wish there was a way to narrow it down. Maybe muffler shop is a good first step

I meant I can hear the spin down whine which is what I normally hear on my starter after start-up. Throwout bearing won't usually cause driveability issues. If you hold the clutch in and rev the engine do you still hear the noise...or do you only hear it at cold start up?

 

[trippytro]

I meant I can hear the spin down whine which is what I normally hear on my starter after start-up. Throwout bearing won't usually cause driveability issues. If you hold the clutch in and rev the engine do you still hear the noise...or do you only hear it at cold start up?

Ill hear it at idle, clutch doesn’t seem to bother it, in or out. When its in gear and cruising it can be heard when you know you pass by a wall and it echoes more making it louder. The reason i lean toward my cats is because i am lowered on 18’s and i do impact the area of the cat/mid pipe very often so in my head i may have jolted something loose.

Sound is usually apparent during cold start though i must say, though driving around last night it was constant

 

[Rockster]

If the noise is present at cold start you can remove the accessory drive belt and start the engine and let it idle only long enough to confirm the noise is present or not.

Be sure you note the proper routing of the belt and its direction before you remove it so you can install it again correctly

If not present, put the belt back on and restart the engine to confirm the noise is present with the belt on.

If the noise is present with the belt removed this indicates the noise comes from some other area other than the accessory drive.

The noise you describe is not a noise that based on my experience is common to a bad converter or a leaking exhaust.

A starter motor can fail to disengage from the flywheel and this can result in a racket.

If the noise is not present with the belt removed, but returns when the belt is installed then this tells you the problem is with the accessory drive system.

Every idler roller bearing, tensioner roller bearing, accessory drive and its bearings are suspect. Also, that the tensioner may not be supplying the necessary level of tension to keep the belt from slipping also is possible.

Look for signs the belt's been sliding over an idler/tensioner roller.

Check the belt for signs of degradation. What is the belt replacement schedule? Is it based on miles only or is there a time component?

With the belt removed check all idler roller bearings and tensioner bearing for excessive play, drag, or one that spins too easily.

Check every accessory drive for excessive bearing play, radial and axial. Likely just one accessory drive will have any play.

My Hellcat has been trouble free in this area but with other cars abnormal noise proved to be a bad water pump with one car. With another car, some noise -- dry bearing sound the first time then an intermittent chirping sound the 2nd time -- proved to be in both cases a bad idler roller bearing, so I have had a noisy accessory drive from a bad water pump and a failed idler roller bearing.

And one time out of the blue a car manifested an abnormal noise. Not much I could do at work so I had the car flat bedded to the dealer and off the flat bed and upon engine start the noise was gone. Long story shot the SA and senior techs told me they see this maybe 6 times a year. What happens is something -- a piece of paper or plastic -- gets into the accessory drive -- and makes a considerable racket but at some point can get out of the accessory drive and the racket ends as suddenly as it appeared. This is what happened on the 30 mile ride to the dealer on the back of the flat bed.

I left the car and the tech checked the engine and its accessory drive over very thoroughly and find no signs of any issues. He had me drive the car similar to how I drove it to work the day it made the noise and no noise appeared. Some piece of paper/plastic got into the accessory drive.

 

[trippytro]

Wow thank you for that info that’s exactly how ill check out what i can this weekend.

 

[trippytro]

Just checked out the car, i went ahead and skipped checking the belts now because i really cant hear it from the belt.

I put the car up, banged the exhaust with a rubber hammer, and i can hear the sounds...

So anywhere i hit the exhaust i can hear a faint rattle which sounds like the sound i posted in the video around 1800-2000 rpm.

I went in and tightened the clamps from the headers to my solo cats, and they had a few turns in them so i tightened both sides, and also the pipes in the back. Sounds still persist so shes gonna have to go to the muffler shop for further diag