Hyundai Sonata 1991 Shop Manual page 41

TROUBLESHOOTING
Symptom
Knocking of crankshaft
and bearing
Piston and connecting rod
knocking
Camshaft knocking
Timing belt noise
Camshaft and valve
mechanism knocking
Compression too low
Oil pressure drop
Oil pressure too high
20-10
GENERAL
Probable cause
Worn main bearing
Seized bearing
Bent crankshaft
Excessive crankshaft end play
Worn bearing
Seized bearing
Worn piston pin
Worn piston in cylinder
Broken piston ring
Improper connecting rod alignment
Worn bearing
Excessive end gear
Broken cam gear
Improper belt tension
Worn and/or damaged belt
Worn sprocket
Worn and/or broken tension adjusting mechanism
Worn and/or damaged tensioner
Improper valve clearance
Worn adjusting screw
Worn rocker face
Worn valve guide
Weakened valve spring
Seized valve
Cylinder head gasket blown
Piston ring worn or damaged
Piston or cylinder worn
Valve seat worn or damaged
Engine oil level too low
Oil pressure switch faulty
Oil filter clogged
Oil pump gears or cover worn
Thin or diluted engine oil
Oil relief valve stuck (opened)
Excessive bearing clearance
Oil relief valve stuck (closed)
Y2OCDOA
Remedy
Replace
Replace
Replace
Replace thrust bearing
Replace
Replace
Replace piston and pin or
connecting rod
Recondition cylinder
Repair or replace
Re-align
Replace
Replace
Replace
Adjust
Replace
Replace
Replace
Replace
Adjust
Replace
Replace
Replace guide
Replace
Repair or replace
Replace gasket
Replace rings
Repair or replace piston
and/or cylinder block
Repair or replace valve
and/or seat ring
Check engine oil level
Replace
Replace
Replace
Change
Repair
Replace
Repair