I have a 2011 Jeep JK that I purchased used with 26K miles on it. It has the 3.8L and is a manual. Previous owner was meticulous with care, and recently I have been bothered by a chirp coming from the engine bay when warm. I have used a stethoscope and narrowed it down to the area around the power sterring pump. I tried the water on the belts, changed the idler pulley and belt tensioner and replaced the belt thinking it was one of them prior to using the stethoscope.
The pump was fine, no issues or leaks, but the chirp definately was coming from there. I ordered a new OEM pump and swapped it out. After the Jeep warmed up, the chirp has now returned. It doesn't change with the clutch being in or out, and definately is coming from the area around the power steering pump. Definately not in the engine block, and all other componets such as the water pump check out OK with the chirp being the loudest when I touch the back of the power steering pump.
This has me stumped, and it is annoying as hell. Any ideas where to look for this? It only does it when warmed up, and the chirp speeds up with engine rpms, yet comes and goes.

 

I have updated this post with a link to a video I took of the chirping noise, hoping someone can help me.
video here

 

Wow, that is a weird one. That isn't like any common chirp I can think of. Have you tried probing around with a mechanic's stethoscope? If you don't have one those are pretty cheap at the auto store and should help at least narrow down a closer range of where it's coming from.

 

Yes I have used the stethoscope, and it is loudest coming from the power steering pump base. I bought a brand new OEM power steering pump and changed fluid, and after it warmed up this noise came back. It only does it when engine is warm, and comes and goes. To date I have replaced the pump, belt tensioner, idler pulley and put another belt on. My mechanic is also totally baffled on what it could be. He said there is nothing behind the pump in the engine block that would cause a sound like that.

 

Take the belt off and spin stuff by hand. But it almost sounds like something is on the belt and only when it passes a high friction area does it make that noise. Like spinnning the PS takes more energy to do and causing that one spot in belt to slip.

I had some crud in the grooves on the crank pulley and it would walk a belt off. The engine alsway stopped right at the point of not being able to see it.

Also take a bar of soap and with engine running let the bar rub on and if the noise goes away you will know its belt related and not something in a alternator or some idler pulley

 

Start with the belt off and start her up. Won't hurt for a couple of minutes.

 

Took the belt off after it was warmed up and chirping fairly constant. Chirping did go away so it is definitely something in the rotating off the belt realm. It is definitely loudest and by stethoscope coming from the power steering pump. Fluid is full and clean, pump is new OEM (not rebuilt) so I am guessing my Jeep just doesn't like the power steering pump. Hate to drop another $200 on another pump when this one was OEM NIB.