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ENGINE INTRODUCTION (J08E)
EN01–9
Diesel knock
Unusual engine noise
Symptom
Possible cause
Remedy/Prevention
Diesel knock (Supply pump)
Damaged suction control valve (SCV)
Replace the suction control valve (SCV)
Use of poor fuel
Use good quality fuel
Diesel knock (Injector)
Breakdown of injector
Replace the injector
Use of poor fuel
Use good quality fuel
Diesel knock (Fuel system)
Use of poor fuel
Use good quality fuel
Diesel knock (Other problems)
Excessively cooled or heated engine
Warm up or cool engine
Insufficient air intake
Correct
Insufficient compression pressure
Repair
Compression pressure leaks at cylin-
der head gasket
Replace head gasket
Improper valve clearance or valve
sticking
Adjust or repair
Tappet sticking
Replace tappet and camshaft
Symptom
Possible cause
Remedy/Prevention
Unusual engine noise (Piston)
Wear of piston pin boss or piston pin
Replace piston and/or piston pin
Seized, damaged, or worn piston pin
bushing
Replace piston pin bushing
Worn pistons or cylinder liners
Replace piston or cylinder liner
Damaged or seized piston
Replace piston and cylinder liner
Foreign matter on top surface of the
piston
Remove foreign matter and repair or
replace piston, cylinder liner, and/or
cylinder head
Unusual engine noise (Valve mecha-
nism)
Incorrect valve clearance
Adjust valve clearance
Valve cotter out of place
Replace valve cotter
Seized valve stem
Replace valve and valve guide
Broken valve
Replace valve
Damaged rocker arm support
Replace rocker arm support
Broken valve spring
Replace valve spring
Unusual engine noise (Bearings sei-
zure)
Insufficient lubricating oil
Add oil
Excessive or insufficient tightening of
bearing housings
Retighten to specified torque
Pits and scratches on bearing surface
Replace bearing and crankshaft
Oil film formed on back of bearing
Replace bearing
Improper installation of bearing
Replace bearing
Reduction of spread dimension of
bearing
Replace bearing
Distorted bearing housing
Replace or correct bearing housing
Excessive oil clearance
Replace bearing