Help me diagnose noise!

[checkedout]

This is driving me nuts! The other nite I'm turning to pull into a parking spot and I hear a loud knocking from under the hood. I sat there and tried to figure out what it was and noticed that if I bring up the RPM a little more it goes away. I was thinking power steering pump because as I sat there and the noise stopped, I turned the wheel just slightly and it would start clanking again. To be sure, I've tied several more times to pinpoint it and I also noticed that the clanking/knocking starts if I put on the A/C too (all while at idle). Yesterday I tried to produce the sound and could not make it happen, this morning it's back. It seems that it mostly appears after an hour or so of driving.
Any suggestions?

 

[Green98XLT]

Tensioner/idler pulley on the front accessory drive. Replace both if you never have, especially with that kinda mileage!

 

[checkedout]

I replaced the tensioner about a year ago. I tried to find it by placing a screwdriver as close as I could to all the shafts but I couldn't feel a difference anywhere.

 

[Green98XLT]

You're a local guy! Good to see another Winchester native on here.

Anyway, Pay real close attention to your idler/tensioner pulleys and the A/C pulley. I'd almost bet thats your noise.

 

[checkedout]

Hey! I didn't notice that. Cool! I think I'm going to go out and remove the belt and see if I can tell anything that way.

 

[Green98XLT]

There you go, just don't run it too long without the waterpump turning...

I'm assuming you have the OHV 4.0?

 

[checkedout]

Yes, I do. I'll let you know if that tells me anything.

 

[checkedout]

Well that didn't help at all. Still stumped

 

[checkedout]

It's tough when the noise is intermittent but I'm starting to think its the flywheel.

 

[checkedout]

That was it. The flexplate was cracked in four places.