Routine 212-Engine Noise

DIAGNOSTIC ROUTINE 212-ENGINE NOISE

System & Component(s)	Reference
SQUEAL, CLICK OR CHIRP Oil Level (Low) Valve Train Drive Belts (Loose) Belt Driven Components EEC Solenoids	Visual and audible inspection.
RUMBLE, GRIND Belt Driven Components	Perform audible inspection.
RATTLE Components (Loose)	Visual and audible inspection.
HISS Vacuum Distribution (Leaks) Inlet Air Control Spark Plugs (Loose) Cooling System (Leaks) Vacuum Operated Components (Leaks)	Visual and audible inspection.
SNAP Secondary Ignition	Visual and audible inspection.
RAP, ROAR Exhaust System (Leaks) EGR System (Leaks) (2.2L)	Visual and audible inspection.
LIGHT TAPPING AT ONE-HALF ENGINE SPEED & NON-VARYING FREQUENCY Excessive Valve Train Clear- ance at Rocker Arm Cam Follower, Valve Stem, Hy- draulic Lash Adjuster or Camshaft Lobe(s)	Check valve clearance.
LIGHT TAPPING AS ABOVE BUT WITH VARYING FREQUENCY COMES & GOES Sticking Valve(s)	Check engine mechanical condition.
LIGHT TO MEDIUM RAP: MOST NOTICEABLE WHEN ENGINE IS COLD AND AT MIDRANGE OF ENGINE SPEED. NOISE TEMPORARILY REDUCED WHEN OIL IS ADDED TO AFFECTED CYLINDER Excess Piston to Cylinder Bore Clearance (Piston Slap)	Check engine mechanical condition.
LIGHT TO MEDIUM RAP EACH ENGINE REVOLUTION. MORE NOTICEABLE AT ENGINE IDLE. SHORTING OUT THE AFFECTED CYLINDER INCREASES NOISE Excess Piston to Piston Pin Clearance	Check engine mechanical condition.
MEDIUM TO HEAVY SHARP KNOCK AT MEDIUM ENGINE SPEED AND AT NO LOAD OR "FLOAT" CONDITION. SHORTING OUT CYL REDUCES NOISE Connecting Rod Bearing(s) to Crankshaft Clearance Excessive	Check engine mechanical condition.
HEAVY, DULL KNOCK OR THUD AT ANY ENGINE SPEED. MORE SEVERE UNDER LOAD Main Bearing to Crankshaft Clearance Excessive Spark Knock Detonation	Check engine mecanical condition, and perform DIAGNOSTIC ROUTINE 215
HEAVY, DULL KNOCK OR THUD. MANUAL TRANSAXLE CLUTCH OPERATION WILL CHANGE NOISE. AUTOMATIC TRANSAXLE STALL CONDITION WILL INCREASE NOISE Flywheel Loose or Cracked	Inspect flywheel.