squealing noise when engine running

[68Malibu383]

2015 V6 with 115k miles. This noise started about 2 months ago and is extremely annoying. Noise starts after I drive about an 1/8th of a mile but then noise stops 30 seconds to one minute after truck stops moving.

It's been difficult for me to diagnose because I'll stop the truck, open the hood and start listening with a screwdriver or Pole pressed on various components but have little time before the noise stops.

If it's making the noise, and I turn the engine off, then restart, noise is not there. I have to drive about 1/8th of a mile before it starts. Everything on the truck works fine.

Here's a link to a vid

 

[Octane]

Pull the belt and spin alternator pulley, should be really smooth and quiet.Do same for other pulleys.You can remove belt and run engine to see if noise is still there,just dont run it hot.

 

[NJMOPAR]

If it's the original at 115k, I'd replace the belt while it's off to check the pulleys.

 

[Michigan BIGHORN]

Holy crap I usually have a good feel for these kinds of things but I've got to admit I'm at a loss. Have to agree with the two posts above me, I immediately thought something belt driven, not the belt but something driven by the belt that starts when the rpms increase from driving? Wish I had more but I don't.....

 

[Sherman Bird]

So, does it change with RPM?

 

[68Malibu383]

So, does it change with RPM?

It It changes some. Seems to go away at certain RPMs

 

[68Malibu383]

Update Update - I removed belt and it made no difference. Noise is still there..

One thing I wonder is if it has something to do with the transmission or torque converter. Transmission was replaced right at 100k under warranty and noise started and round 112,000 miles.

 

[Sherman Bird]

I had a mid 80's 300ZX Nissan with automatic transmission in my shop back in the late 80's with a mysterious low pitch "Whooshing noise upon decel. It sounded JUST like a vacuum leak at the low end of the pitch spectrum. By the time the customer was referred to my shop, he had been to 4 other places including a dealer... and none could figure it out. Keep in mind this car ran fine! We went snipe hunting for the "vacuum leak".... and spent a whole day on it with me and my lead tech. Lead tech decides to get out the stethescope and determined the noise to be eminating from the lower bell housing region! WTF! Thechnician removed the trans pan and it was full of huge aluminum shavings. We sold a tear down and found no reason for the problem in the transmission itself. We sent the torque converter out to be cut open and Voila!, the stator (made of aluminum) had stripped the splines of where it engaged the front pump... the "Whooshing" noise was the stator freewheeling!

 

[SRLMARK]

I have the same noise! But it only happens at a tick above 2k rpm. It's only been happening for the last week or so. Hmm.

 

[68Malibu383]

That's about where mine is the loudest and I can hear it when driving.

The only update I have is that I pulled into my driveway the other day and it was making the noise. Turned engine off and my passenger got out and slammed the door as most chicks do and there was one small chirp.

So then I thought maybe running boards or exhaust was vibrating and loose but pryed on everything and still can't figure it out.

 

[SRLMARK]

I can only get mine to make the noise while driving. But it's getting more noticeable so I'm sure it will be getting to be like yours in short order. So if you can find out where it's coming from let me know and I'll do the same if I can figure it out. I'm just shy of 87k miles.

 

[68Malibu383]

I will definitely post back if I figure it out.

 

[68Malibu383]

I've figured out where the noise is coming from, but I've not found the solution yet. Noise is coming from driver's side exhaust where cat converter pipe connects to manifold. There is a brace welded to the exhaust pipe right there and if I pry with a screwdriver, noise goes away. I will try torquing pipe to manifold bolts. If that does not work, I'll take a hammer and change the shape of that brace (diameter of a pencil) a little bit.

 

[SRLMARK]

Awesome I'll check mine tomorrow!

 

[68Malibu383]

I tightened the exhaust manifold bolts and that did not help. I don't know the torque spec, but one was fairly loose. Unfortunately, that did not help. I've checked all other exhaust bolts and nothing else was loose.

If I put a screw driver between pipe/cat converted and the brace (red mark in pic), the noise goes away. My next move may be to take a BFH to the brace and change its shape a little.

 

[68Malibu383]

I just fixed the problem. The rod was cracked by the exhaust manifold/head flange, so I welded it. Amazing how much noise that made and the type of noise. I circled the cracked area but it was nearly impossible to see.


View media item 30086

 

[SRLMARK]

So that fixed it completely? Sounds like I need to get on it my next day off!

 

[68Malibu383]

Yes, it is fixed now. After I repaired that, I could hear the engine ticking from a bad rocker arm. That's another post...