Engine Noise Diagnosis
Engine Knock Noise (Fuel Knock)
Intermittent Noise on Idle Only, Disappearing When Engine Speed Is Increased
Noise at Slow Idle or With Hot Oil; Quiet at Higher Engine speeds or With Cold Oil
Noise at High Vehicle Speeds, Quiet at Low Vehicle Speeds
Noise Regardless of Engine speed
Valve Train Noise.
Vibrating or Rattling from Exhaust System
Exhaust Leakage and/or Noise