A few days ago I began noticing a squeaking sound coming from my engine (2000 4.0 OHV). I'm getting to about 3,000 miles from my last oil change and I was planning on changing it before I went back up to school next Saturday. The squeaking is consistent with the RPM but is intermittent: sometimes it squeaks like crazy and other times it’s silent. My first thought was a belt or an accessory. I put water on the belt while it was squeaking to see if it made a difference and it didn’t. I next used a dowel (for lack of a stethoscope...) to listen to my power steering pump, my alternator, my idler, and my water pump which all checked out. It almost sounds like its coming from the rear of the engine. I did some research and is sounds like it could be the cam position sensor. I don't have a ton of time to goof around with it since I've got a 300 mile trip next Saturday so chances are I'll drop it off at the dealership and let them screw with it...I just want a basic idea of what it could be so they don’t come back and try to take me for an idiot and tell me that my alternator, belt, water pump, and whatever else are bad...especially since they replaced the alternator and belt about 6 months ago. I included a video in case it's of any help. Thanks in advance.

 

Also check the front idler pulley bearing.

 

well it sure does sound like the cam synchro did on my 3.0... i didnt know that the 4.0 had them though

 

Pull the belt off and check the fan clutch and the water pump, I had a bad squeel a while back and thought it was the idler pulley but the bearing in the water pump was shot and cause the fan clutch to bad as well.