01 4.0 with 180k on it. Noise started yesterday, its a constant noise, almost sounds like a skateboard rolling down pavement, it seems to be coming front the front of the motor specifically the alternator but its so loud with the hood up I can't pin point it. I'm just trying to know what to expect before going to the shop.

I searched around a few different forums with no exact results, only things I could narrow it down to were idler pulley, alt, water pump but I figured posting a thread would yield some better results for me.

Thanks guys

 

Take your belt off and roll all the accessories over by hand and see if you have a bearing on it's way out?

 

Or if you don't want to remove your belt, use a long screwdriver or even better a prybar with the end up to each accessory, and your ear on the handle. it works just like a stethoscope, and narrowing down the bad bearing will be obvious

 

That's an excellent diagnostic practice just BE CAREFUL around the belts and pulleys!!

 

that was the sound ours was making saturday it ended up being the alternator

 

May just be me but it seems like its getting louder, there's also a ticking/jiggling noise coming from the altenator

 

do you have an amp guage on the dash if so check the output readings

 

alternator!

 

Amp guage reads jujst under 14 and its running just fine. Real hard to pinpoint but the skateboard noise sounds like it may be coming from the rear of the block? Its jsut so loud with the hood up I really can't tell

 

Im trying a whining noise as well can't tell were its coming from. It gets louder with rpm almost sounds like a gear drive whine fluids are all fine

 

Having*

 

I'm bringing this back from the dead to hear if there is any additional input here... OP, ever find the source?

 

could be the belt alone, could be that your alternator has a short that causes the pulley face to seize and thus squeal. when this happens, the amp gauge drops to near 0, lights dim. power steer just goes out, same with water pump, Pray for god no heater pump, and idler is easy

 

could be a fan hitting the shroud if everything else checks out.