Subaru 2009 IMPREZA Service Manual page 1165

Symptom
8. Knocking
9. Excessive engine oil
consumption
10. Excessive fuel
consumption
Engine Trouble in General
Problem parts etc.
Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>
Intake system
Timing belt
Compression
Cooling system
Intake system
Compression
Lubrication system
Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>
Intake system
Timing belt
Compression
Lubrication system
Cooling system
ME(H4DOTC)-107
Possible cause
Loosened oil filler cap
Defective timing
Incorrect valve clearance
Incorrect valve timing
Over-heating
Loosened or cracked PCV hose
Defective PCV valve
Loosened oil filler cap
Defective valve stem
Worn or stuck piston rings, cylinder and piston
Loosened oil pump attaching bolts and defective gasket
Defective oil filter gasket
Defective crankshaft oil seal
Defective rocker cover gasket
Loosened oil drain plug or defective gasket
Loosened oil pan fitting bolts or defective oil pan
Dirty air cleaner element
Defective timing
Incorrect valve clearance
Loosened spark plug or defective gasket
Loosened cylinder head bolt or defective cylinder head
gasket
Improper valve sealing
Defective valve stem
Worn or broken valve spring
Worn or stuck piston rings, cylinder and piston
Incorrect valve timing
Incorrect oil pressure
Over-cooling
MECHANICAL
RANK
A
B
B
C
B
A
A
B
C
A
A
B
B
B
B
B
B
A
A
B
B
C
C
B
C
C
B
B
C
C