OPQRST Onset, Provoking, Quality, Radiation, Site, Timing. Onset: When did or does it start ? Provoke: What makes it better or worse ?,
Quality: High pitched or low, tinny, plastic ?, Radiate ? Does it effect anything else ?, Site: What is actual spot of noise ? Timing: First
starting up ?Only when warm ?
THEN HIFI - History, inspection, feel, instrumentation. Anyone do work lately ? Look everywhere ? Feel with hands for tick. Listen with stethoscope. Put cell phone here and there to listen for loudness.
Those are taken from the medical model but some may be helpful. Second opinion from another mechanic ? Good luck !