1997 2500 5.9 v8

Hit a hard bump tonight and almost instantly developed an engine noise. The best way I can describe the noise is when you vacuum up a penny. I looked under the hood and every moving part on the outside seemed to be in order.

I've ran out of things to look at, but I'll bet I missed something obvious. Truck still runs and drives fine, just now has the noise.

Any input is appreciated.

 

I would check the tranny cooler lines and see if they are touching the harmonic balancer or if anything got into the fan shroud. I've seen the tranny cooler lines rub up on the balancer on a few rams and make that noise. They also will vibrate on the drivers side of the block between the starter & motor mount. Try checking that out as a starting point.

 

Well I found the problem. The guy before me put a pos aftermarket pulley in place of the air conditioner and the belt slipped out of alignment. I think the bearings in the pulley have about had it and caused the noise. Thankfully it was an extremely simple fix.