If your dipstick tells you that the oil level is acceptable, and that noise shows up (I'm assuming a tick or some indicator of starvation), I'd start with the oil pick-up tube in the oil pan. Given the number of miles, the screen may be clogged or delivery to the oil pump might be hampered by a loose tube. Pump could even be shot. Just a guess, but that was the first thing that came to mind.
Todd