Mitsubishi 4DQ50 Service Manual page 74

Probable cause Possible remedy
Low
oil pressure
Defective oil pump
Repm.
-cont. Clogged fuel lines Flush.
Defective oil pressure valve
Repajr and replace if necessary
Clogged oil filter Change element and oil.
Leak
in lubricating system
Repair.
Pumping up of oil
Excessive oil in oil pan
Drain oil to lower oil level.
Worn cylinders, pistons or Repm and replace parts if neces-
piston rings sary
Sticking piston rings Repair and replace damaged rings
if necessary.
Worn valve guides
Replace valve guides.
Prolonged operation under no
Overhaul engine if oil -laden gases
load are exhausted.
Insufficient m Clogged air cleaner Clean and replace element if
(paper element type)
necessary.
Clogged air cleaner Wash interior.
(Oil bath type)
Clogged intake manifold Check and clean.
Poor compression Defective valve seats
Repajr
Sticking valve stems Repm and replace valve stems
if necessary
Failure of rocker arms to Adjust valve clearance to 0.3 mm
lift valves
(0.OI2mm).
Worn cylinder, pistons or
Repair and replace
parts
if neces-
piston rings
sary.
Sticking piston rings
Replace damaged rings.
Exhaust
gas
leak in cylinder
Retighten and replace gasket
if
head gasket necessary.
Worn or broken valve springs Replace parts.
Jnsufficient torque of starting
motor
(at starting)
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