User Manual

48 RENR9968-02
Testing and Adjusting Section
10. Check for loose drive belts.
a. A loose fan drive belt will cause a reduction in
the air flow across the radiator. Check the fan
drive belt for proper belt tension. Adjust the
tension of the fan drive belt, if necessary. Refer
to Operation and Maintenance Manual, “Belt -
Inspect/Adjust/Replace ”.
b. Worn gears within the water pump will cause a
reduction in coolant flow through the radiator.
Check the gears within the water pump for any
worn edges.
11. Check the cooling system hos es and clamp s.
Damag ed hos es with leaks can normally be seen.
Hoses that have no visual leaks can soften during
operation. The soft areas of the hose can become
kinked or crus hed du rin g o pe ration. T he se areas
of the hose can cause a restriction in the coolant
flow. Hoses become soft and/or get cracks
after a period of time. The inside of a hose can
deteriorate, and the loose particles of the hose
can cause a restriction of the coolant flow. Refer
to Operation and Maintenance Manual, “Hoses
and Clamps - Inspect/Replace”.
12. Check for a restriction in the a ir inlet system.
A restriction of the air that is co ming into the
engine can cause high cylinder temperatures.
High cylinder temperatures require higher than
normal temperatures in the cooling system. Refer
to Testing and Adjusting, “Air In let and Exhaust
System - Ins pect”.
a. If the measured restriction is higher than the
maximum permissible restriction, remove the
foreign material from the engine air cleaner
element or install a new engine air cleaner
element. Refer to Operation and Maintenance
Manual, “Engine Air C leaner Element (Dual
Element) - Cle an/Replace”.
b. Check for a r estriction in the air inlet sy s te m
again.
c. If the measured restriction is still higher than
the maximum permissible restriction, check the
air inlet piping for a restriction.
13. Check for a restriction in the exhaust system.
A restrictio n of the air that is com i ng out of the
engine can cause high cylinder temperatures.
a. Make a visual inspection of the exhaust system.
Check for damage t o exha ust piping or for a
damaged muffler. If no damage is found, check
the exhaust s ystem for a restriction. Refer to
Testing and Adju sting, “Air Inlet and Exhaust
System - Inspect”.
b. If the measured restriction is higher than the
maximum permissible restriction, there is a
restriction in the exhaust system. Repair the
exhaust system, as required.
14. Check the water temperature regulator. A water
temperature regulator that does not open, or a
water temperature regulator that only opens part
of the way can cause o verheating. Refer to Testing
and Adjusting, “Water Temperature Regulator -
Tes t” .
15. Check the water pump. A water pump with a
damaged impeller does not pump enough coolant
for c orrect engine cooling. Remove the w ater
pump and check for damage to the impeller. Refer
to Testing and Adjusting, “Water Pump - Test”.
16. Check the air flow through the engine
compartment. The air flow through the radiator
comes out of the engine compartment. Ensure
that the filters, air conditioner, and similar items
are not installed in a way that prevents the free
flow of air through the engine compartment.
17. Consider high outside temperatures. When
outside temperatures are too high for the rating
of the c ooling system, there is not enough of a
temperature difference between the outside air
and coolant te mperatures.
18. Consider high altitude operation. The cooling
capacity of the cooling system goes down as
the engine is operated at higher altitudes. A
pressurized cooling system that is large enough to
keep the coolant from boiling m ust be used.
19. The engine may be running in the lug condition.
When the load that is applied to the engine is
too large, the engine will run in the lug condition.
When the engine is running in the lug condition,
engine rpm does not increase with an increase of
fuel. This lower engine rpm causes a reduction
in air flow through the radiator. This lower engine
rpm also causes a reduction in coolant flow
through the system. This com bination of less air
and less coolant flow during high input of fuel will
cause above normal heating.
i02228221
Cooling System - Inspect
SMCS Code: 1350-040
Cooling systems tha t are no t regularly inspected are
the cause for increased engine temperatures. Make
a visual inspection of the cooling system before any
tests are performed.