I have heard that the heat shield on a catalytic converter can frequently come loose and rattle a bunch, Also check the heat shields under the exhaust manifolds and by the y-pipe.

 

I had forgotten, my 96 did that. It was at lower RPM though. Idle and just above.

 

Will do. Thanks!

 

Since I had some more time behind the wheel yesterday. it does not make the same tick as it did before, now I can barely hear a tick at 2500-2800.

 

I was watching my needle and it gets right on top of the "2". I may try a flush too!

 

I started disconnecting the spark plug wires one at a time and when I got down to the #5 wire the rattle went away. Is there anything else besides a rod bearing this could be? Like I said before, I dropped the oil pan and there was no metal shavings in the pan, and when I tried moving the rods, the rods were tight. I didn't use any plastic gauge to check them, I just grabbed ahold of the caps and tried movng them. With the stethoscope I put the probe on the heat shield beneath the area under the #5 plug and you could hear the rattle (from 1800-2500 rpms) pretty plainly. Underneath the truck I put the probe on the shallow (front) end of the oil pan and you could hear it there as well, but not as plainly. I realize this can be a little decieving due to the way sound travels. As you may can tell, I am really hoping this is not the bearings!!

 

I don't think it's a rod bearing. A bad rod bearing will make a distinctive knocking sound at idle which you don't have. I'm starting to think you've got a rattling exhaust valve. Have you checked the valve springs for #5?

 

No I haven't. As a matter of fact I just told my wife a few minutes ago that was what I was going to check next! Am I looking for a loose rocker arm, broken spring? What about the push rod?

So a bearing always makes noise at idle also? When the truck is idleing it is pretty quiet other than the ticking of the injectors. You can't really hear this until around 1800 rpm and its the loudest at 2300-2500 rpm. And only after its at least halfway warmed up.

I cut the oil filter open and it looked clean. The only metal I seen came from where I sawed it in half. I pulled the pleats back and they were clean.

Thanks for giving me hope!!

 

What if the exhaust manifold is leaking?

 

Every one I've ever run across does. Once, on a SB Chevy, I forgot to torque a rod cap. It was just wrench tight, so when it began to back off, it knocked so loud at idle that the neighbors could hear it.