Strange engine noise problem - 2004 Liberty 3.7L

[jimithing78]

This just started on the way home from work tonight. I caught a red light and stopped to wait for it to change. When I stopped I heard the engine not idling normally and turned down the radio to hear what's in the video below. The engine seems to be running ok, it's not overly rough, it still has plenty of power. No check engine lights or anything like that. Just the sound.

We bought it used at about 50k and it has about 98k on it right now. It's had Mobil 1 oil/filter changes every 5k miles since then. I haven't ever changed the serpentine belt and I was thinking about trying that tomorrow but I'm not sure if that will help. I thought belts normally squeal when they're slipping. My other thought is that one of the pulleys has some bearings going bad. I'm no expert, though, I could be way off. What do you guys think?

Video:

2004 Jeep Liberty Engine Noise - YouTube

edit: I tried to embed the video but it doesn't appear to be supported here. If someone else knows how please feel free.

 

[Porkchop]

It sounds like a bearing. Idler,tensioner, AC, alt, water pump, dont know take off the belt turn each one by hand you should be able to feel witch one is going bad if not try changing the belt and than you would have a spare for emergencies. I would change the belt after replacement of a pulley or bearing anyways just for the spare.

 

[jimithing78]

Well just went and loosened the belt. The tension wheels spin ok. There's a little noise on one of them but not bad. The a/c compressor was pretty hard to turn, though. I'm guessing that's my culprit. With the engine off and the belt remove I should have no trouble turning that, right? I think the a/c switch was on inside the car but that shouldn't matter with everything off.

 

[Porkchop]

Ya it should turn freely and the AC cluch is not engaged until power is applied to it even at that the AC compressor should turn easily. I would replace any other I though was going bad as well if any of them lock up there goes the belt.

 

[dude1116]

X2 with the bearings! Get'm checked!

 

[yellocoyote]

Video:

2004 Jeep Liberty Engine Noise - YouTube

edit: I tried to embed the video but it doesn't appear to be supported here. If someone else knows how please feel free.

Here ya go...

[YT]WYFiTNXGwhE[/YT]

 

[sevenhelmet]

Yup, you've got a bad bearing somewhere.

 

[port67]

Well just went and loosened the belt. The tension wheels spin ok. There's a little noise on one of them but not bad. The a/c compressor was pretty hard to turn, though. I'm guessing that's my culprit. With the engine off and the belt remove I should have no trouble turning that, right? I think the a/c switch was on inside the car but that shouldn't matter with everything off.

Not sure if this will fix the problem but replace the tensioner and pulleys. That small noise will be amplified when under load. I had a bad rattling noise that sounded like some thing was loose in the engine. Replaced the tentioner and pully and all is well again.