isc fuel pump?

[hookliftpete]

Earlier this week I removed a couple of items from the exterior of the truck (2008 isc in a pete 335, just broke 100k miles) (auto tarp/gantry no longer used) which were making a whistle when driving above about 30mph. I thought that I could hear some other noises, but was unable to tell with the wind noises on the tarper.

With that noise gone, I've got some sort of mechanical noise (metalic/clinking) which is audible above 1500 rpm and up. Gets louder with rpms, especially with fan/ac turned on.

In the meanwhile, the fuel pump has had a very small leak. Is the pump likely the culprit? Truck does not start hard, mileage has been steady. I assume this thing does not have a ceramic pump like some of you with isx engines have...

Checked the pulleys on the front of the block, nothing appears to be loose/sloppy.

Also, cummins lists the overhead as needing done at 100k miles. Would that make noise if out of adjustment? When I did the injectors, everything under the valve cover looked good, no shavings or flecks, no wear that I could see.

It's in for inspection Friday, but I'm hoping to have an idea as to what I'm in for before then, if this is a major issue...prob is, so I've learned over the last year.