Isuzu 2000 Trooper Workshop Manual page 729

6A–16 ENGINE MECHANICAL
Engine Oil Consumption Excessive
Condition
Oil leaking
Oil leaking into
chambers due to oor seal in valve chambers due to poor seal in valve
system
Oil leaking into
chambers due to poor seal in cylinder
parts t
Positive Crankcase
System malfunctioning
Others
Possible cause
Oil pan drain plug loose
Crankcase fixing bolts loosened
Oil pan setting bolts loosened
Oil pan gasket broken
Front cover retaining bolts loose or
gasket broken
Head cover fixing
gasket broken
Oil filter adapter cracked
Oil filter attaching bolt loose or rubber
gasket broken
Crankshaft front or rear oil seal
defective
Oil pressure unit loose or broken
Blow–by gas hose broken
Positive Crankcase Ventilation Valve
clogged
Engine/Transmission coupling failed
combustion Valve stem oil seal defective
Valve stem or valve guide worn
combustion Cylinders
excessively
Piston ring
positioned
Piston rings set with wrong side up
Piston ring sticking
Piston ring and ring groove worn
Return ports in oil rings clogged
Ventilation Positive Crankcase Ventilation Valve
clogged
Improper oil viscosity
Continuous
and/or severe usage such as trailer
towing
bolts loose or
and pistons worn
gaps incorrectly
high speed driving
Correction
Retighten or replace gasket
Retighten
Retighten
Replace gasket
Retighten or replace gasket
Retighten or replace gasket
Replace
Retighten or replace oil filter
Replace oil seal
Retighten or replace
Replace hose
Clean
Replace oil seal
Replace
Replace valve and valve guide
Replace cylinder body assembly and
pistons
Correct
Correct
Replace cylinder body assembly and
pistons
Replace pistons and others
Clean piston and replace rings
Clean
Use oil of recommended S.A.E.
viscosity
Continuous high speed operation
and/or severe usage will normally
cause increased oil consumption