I just bought this machine, and don't have much experience with diagnosing Diesel engines but here goes; the machine is a 99 or 2000 with 9700hrs, and I've only run it for about 6 hours so far. Today, I noticed a change in the engine noise up at higher rpms. It wasn't constant, seemed to come and go, a hum or whine, but it wasn't particularly smooth sounding from where I sat, I didn't think. Also, on what i thought was the return lines, the fitting over one of the injectors the fitting was on a little **** eyed or cross threaded and seemed to be leaking some fuel. Could this be related? Does the noise just sound like the normal noise of the turbo engaging? Thanks for any input!
You wouldn't believe the horrible noises I've cured with a shot of belt dressing. Check that first. Also check that your water pump and alternator bearings are good. After that you can start to worry.
Could be a belt all right, or a rough bearing anywhere something's turning, worn pumps, hydraulic issue, cooling fan, turbo, or turbo to intake air leak, etc., etc..... With that many hours, could easily be the engine to pump coupler coming apart, depending on what type of coupler it actually is, plate, segment, donut, etc... Good luck.
I find loose or missing steel boom line clamps make some really interesting noise while working but lantraxco is right could really be anything. You'll have to have someone run it and listen for the noise. The fuel tees are common, they get cross threaded all the time. Easy fix