Hey guys,

My 2006 4.0 has about 103k miles on it and has been making a noise from the engine. Doesn't happen all the time and I feel like it varies in loudness. I believe it goes away when I turn the a/c on. I have a couple videos here of where I think its coming from. My mechanic briefly listened today and agreed it could be the area, but also thought he heard something internal. We didn't get much futher due to lack of time this evening. I would appreciate any tips to stear me in the right direction if you've heard something similar.

https://www.dropbox.com/s/nbyjudglhn...%20PM.mov?dl=0

https://www.dropbox.com/s/biti5ds231...%20PM.mov?dl=0

 

AC compressors clutch bearing can make noise when AC is off and then since it isn't spinning free, no noise when AC compressor is ON.

For internal noises
With engine stone cold, sitting overnight
Loosen fan belt tensioner and remove fan belt from crank pulley, drive pulley
So now no fan, no Alternator, no AC, no pulleys at all
Start engine
It will be very quiet in engine bay so you can track down any internal noises

You can ONLY run engine for 2 minutes this way, no water pump, so turn it off
Hook up fan belt and restart to circulate coolant again.

Battery light will be on during test with no alternator.