Help Identifying Engine Squeal/Whistle

[ShredAZ]

Here's the gist of it:
The engine has been squealing when under loud and high RPM (3000+) and typically only when the fan is engaged.

I can recreate the sound at idle but only when the fan is engaged and the engine is hot. AC has no noticeable affect on when the sound is triggered.

Here's what's been replaced:

• PS Pump (<100 Miles)
• Auto Tensioner Assembly (<100 Miles)
• HD Fan Clutch (6000 Miles)
• Gates Belt (6000 Miles)
• Mopar Water Pump (<100 Miles)

I've checked all pulleys for play and/or noise. Everything seems to be nice and tight.
I'm hesitant to pull the belt and open the throttle. Since the noise only occurs under high heat/load, I'm fearful it'll do some damage.

At this point, I'm about out of ideas. Open to see if anyone else has thoughts as its driving me CRAZY.

I'm dropping her off at the local Jeep dealership tomorrow. I'm hoping they can shed some light on the issue. I'll keep the thread updated.

 

[CodaMan]

Did you try tightening the intake/exhaust manifold bolts? They tend to get loose which then causes a whistle when sucking air.

 

[ShredAZ]

Did you try tightening the intake/exhaust manifold bolts? They tend to get loose which then causes a whistle when sucking air.

Ah I think you're onto something! I have started to wonder if I have an intake leak somewhere.
I'll be honest, I only checked the tension of the back two manifold bolts as those are the ones (I understand) typically loosen. I haven't checked the others yet.

 

[CodaMan]

I had the same problem on my last TJ. The problem is, the gasket may have leaked so long that tightening it may have no affect or only very short term affect. I ended up replacing the gasket and all was better.

 

[CodaMan]

Could also be around the throttle body. Get a can of brake cleaner or something, and while the engine is running spray around all the intake areas and vacuum lines and see if the engine revs up.

 

[TJ2]

Idle pulley "tensioner" The spring is weaker due to age.

 

[kylepresnell419]

Does yours sound like this? I know this usually happens to 05-06 year


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[CodaMan]

Idle pulley "tensioner" The spring is weaker due to age.

He already replaced as noted in the original post.

 

[TJ2]

He already replaced as noted in the original post.

oops.

 

[ShredAZ]

Does yours sound like this? I know this usually happens to 05-06 year


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Definitely not! I already replaced the ODPA as well. Good idea though!

 

[Boinked]

Almost sounds like ac compressor pully.

Im hearing a high pitch ring. Like you hit two pieces of metal and slid them.

Only other thing is a barring that might be going out. (accessory not engine) It really tough to tell. Video is very short.

 

[Ben]

Mine has the exact noise, only does it under wot. It sounds almost like a blow off valve on a turbo. No other symptoms than the high pitch whistle so I haven't bothered with it yet lol. Keep us updated if you figure it out.

 

[ShredAZ]

Update:

Jeep was able to recreate it 4 different times.
They identified the noise was coming from the intake area (as we suspected) and not a pulley bearing,
They pulled apart the intake to inspect and found nothing.
After reassembling, they were unable to recreate the noise.

They're going to try again a few more times tomorrow, but it could have been an issue with the ridiculous aftermarket intake that came with the Jeep. Hoping it's something that simple. Rather ironic I didn't think to inspect the intake...a FREE fix. I jumped right into replacing parts haha!

 

[Boinked]

Thank you for the update.
This will be helpful for others.

 

[ShredAZ]

Thank you for the update.
This will be helpful for others.

I sure hope so! It's been driving me crazy.

I'll confirm when I pick it up.

 

[CodaMan]

....Rather ironic I didn't think to inspect the intake...a FREE fix. I jumped right into replacing parts haha!

That is very common. I encourage everyone to understand the problem, think it through and perform smart troubleshooting. It can save a lot of frustration, time and most of all .. $$$

 

[ShredAZ]

Turns out it wasn't the intake. The hunt continues.

 

[Boinked]

Turns out it wasn't the intake. The hunt continues.

Damn. You can try attaching a gopro or 2 under the hood and take it out for a spin around the block. Might see something. Of might be able to narrow down the location.

 

[ShredAZ]

Damn. You can try attaching a gopro or 2 under the hood and take it out for a spin around the block. Might see something. Of might be able to narrow down the location.

The Jeep is still with the dealership. Hoping to have some more ideas tomorrow.

 

[ShredAZ]

Ran into a snag with the diag.

Jeep tech called today and said he found a slow drip on the Mopar water pump I just had replaced.
Obviously coolant on the belt causes slippage. I don't think this is the smoking gun, just an unfortunate road block.

Picking up the jeep Saturday to get the water pump taken care of (again). I'll also be removing the TB spacer the PO installed while I'm at it just to weed out any low hanging fruit.

Fun fact. The dealership wanted $160 to remove the TB spacer