ENGINE
STW34, STW37, STW40, WSM
1-S4
9Y1211109ENS0001US0
Lubricant Oil
Consumption Is
Excessive
1. Piston ring's gap faces the
same direction.
Shift ring gap direction. 1-S57
2. Oil ring is worn or stuck. Replace oil ring. 1-S58
3. Piston ring groove is worn
out.
Replace piston and piston ring. 1-S57,
1-S58
4. Valve stem and valve
guide is worn out.
Replace valve stem and valve guide. 1-S50
5. Crankshaft bearing and
crank pin bearing is worn
out.
Replace crankshaft bearing and crank
pin bearing.
1-S61
Fuel Is Mixed into
Lubricant Oil
1. Injection nozzle stuck or
clogged.
Replace or replace injection nozzle. 1-S48
2. Engine oil is diluted due to
regeneration.
Change engine oil. 1-S20,
1-S31
Water Is Mixed into
Lubricant Oil
1. Head gasket is damaged. Replace head gasket. 1-S49
2. Cylinder (crankcase) or
cylinder head is flawed.
Replace cylinder (crankcase) or cylinder
head.
1-S49
Oil Pressure Is Low 1. Engine oil is insufficient. Fill engine oil. G-8
2. Oil strainer is clogged. Clean oil strainer. 1-S56
3. Relief valve is stuck with
dirt.
Clean relief valve. –
4. Oil clearance of moving
parts is excessive.
Replace moving parts. 1-S74,
1-S75,
1-S76
5. Oil passage is clogged. Clean oil passage. –
6. Different type of oil is used. Use specified type of oil. G-8
7. Oil pump is damaged. Replace oil pump. 1-S55
Oil Pressure Is High 1. Different type of oil is used. Use specified type of oil. G-8
2. Relief valve is damaged. Repair or replace relief valve. –
Engine Is Overheated 1. Engine oil is insufficient. Fill engine oil to proper level. G-16
2. Fan belt is broken or
elongated.
Change or adjust fan belt. G-26
3. Coolant is insufficient. Fill coolant. G-35
4. Radiator net and radiator
fin is clogged with dust.
Clean radiator net and radiator fin. –
5. Inside of radiator is
corroded.
Clean inside of radiator or replace
radiator.
G-35
6. Coolant flow route is
corroded.
Clean coolant flow route. G-35
7. Radiator or radiator cap is
damaged.
Replace radiator or radiator cap. 1-S16
8. Engine is running under
overload condition.
Reduce the load. –
9. Cylinder head gasket is
damaged.
Replace cylinder head gasket. 1-S49
10.Unsuitable fuel is used. Use specified fuel. G-8
Symptom
Probable Cause and
Checking Procedure
Solution
Reference
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