rattling under my explorer

[icke.is.right]

its a 2001 explorer sport. at first i thought it was one of those heat shields. but they are all tight. when the vehicle was running i used a creeper and went all around it. the rattling is definitly coming from the front end. it sounds like its coming right from under the serpentine belt. any suggestions to what it could be will be greatly appreciated.
Thanks

 

[Stick_man]

What's your mileage? I used to have the loudest most annoying rattle on my '98. Everyone said heatshield or exhaust. But when I finally changed the pcv valve it went away for good. Although my truck had 125k when I did it and his been making the noise since 110k.

 

[icke.is.right]

it has just under 180,000

 

[BREN5.0]

mine makes a sound to

 

[97sprt4x4]

does the motor sounds anything remotely like i diesel??? if so it could be the death rattle that is common with the SOHC motor. it may not be, but it's the only thing that comes to mind with the information given.