User Manual

RENR9968-02 49
Testing and Adjusting Section
Personal injury can result from escaping fluid un-
der pressure.
If a pressure indication is shown on the indicator,
push the release valve in order to relieve pressure
before removing any hose from the radiator.
1. Check the coolant level in the cooling system.
Refer to Operation and Maintenance Manual,
“Cooling System Coolant Level - Check”.
2. Check the quality of the coolant. The coolant
should have the following properties:
•
Color that is simila r to new coola n t
•
Odor that is similar to new coolant
•
Free from dirt and debris
If the coolant does not have these properties,
drain the system and flush the system. Refill
the cooling sy ste m with the correct m ixture of
water, antifreeze, and coolant conditioner. Refer
to Operation and Maintenance Manual, “Refill
Capacities and Recommendations”.
3. Look for leaks in the system.
Note: A small amount of coolant leakage across
the surface of the water pump seals is normal. This
leakage is required in order to provide lubrication for
this type of seal. A hole is provided in the water pump
housing in order to allow this coolant/seal lubricant
to drain from the pump housing. Intermittent leakage
of small amounts of coolant from this hole is not an
indication of water pump seal failure.
4. Look for air or combustion gas in the cooling
system.
5. Inspect the filler cap, and check the surface that
seals the filler cap. This surface must be clean.
i02779025
Cooling System - Test
SMCS Code: 1350-040; 1350-081
This engine has a p ressure type cooling system. A
pressure type cooling system has two advantages.
The cooling system can b e operated in a safe manner
at a temperature higher than the no rm a l boiling point
(steam) of w ater.
This type of system prevents cavitation in the water
pump. Cavitation is the forming of low pressure
bubbles in liquids that are caused by mechanical
forces. A pressure type cooling system helps to
prevent pockets of air from forming.
g01106438
Illustrat
ion 37
Effects of pressure on boiling point of a cooling system
Temperature and pressure work together. When
a diagnosis is made of a cooling system problem,
both tempe
rature an d pressu re must be checked.
Cooling sy stem pressure will have an e ffect on the
cooling syst em temperature. For an example , refer to
Illustra
tion 37 . This w ill show th e effect of pressure
on the boiling point (steam) of water. This will a lso
show the effect of height a bove sea level.
Persona
l injury can result from hot coolant, steam
and a lkali.
At opera
ting temperature, engine coolant is hot
and under pressure. The radiator and all lines
to heaters or the engine contain hot coolant or
steam. A
ny contact can cause severe burns.
Remove filler cap slowly to relieve pressure only
when en
gine is stopped and radiator cap is cool
enough to touch with your bare hand.
Coolin
g System Conditioner contains alkali. Avoid
contact with skin and eyes.
The co o
lant must be to the correct level in order to
check the coolant system. The engine must be cold
and the engine must not be running.