5.
Inspect the blades of the fan for damage.
6.
Look for air or combustion gas in the cooling
system.
7.
Inspect the radiator cap for damage. The sealing
surface must be clean.
8.
Look for large amounts of dirt in the radiator core.
Look for large amounts of dirt on the engine.
9.
Shrouds that are loose or missing cause poor air
flow for cooling.
i02414661
Cooling System - Test
Remember that temperature and pressure work
together. When a diagnosis is made of a cooling
system problem, temperature and pressure must be
checked. The cooling system pressure will have an
effect on the cooling system temperature. For an
example, refer to Illustration 36 . This will show the
effect of pressure on the boiling point (steam) of
water. This will also show the effect of height above
sea level.
Illustration 36
g00286266
Cooling system pressure at specific altitudes and
boiling points of water
Personal injury can result from hot coolant, steam
and alkali.
At operating temperature, engine coolant is hot
and under pressure. The radiator and all lines to
heaters or the engine contain hot coolant or
steam. Any contact can cause severe burns.
Remove filler cap slowly to relieve pressure only
when engine is stopped and radiator cap is cool
enough to touch with your bare hand.
The coolant level 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.
After the engine is cool, loosen the pressure cap in
order to relieve the pressure out of the cooling
system. Then remove the pressure cap.
The level of the coolant should not be more than
13 mm (0.5 inch) from the bottom of the filler pipe. If
the cooling system is equipped with a sight glass, the
coolant should be to the correct level in the sight
glass.
Making the Correct Antifreeze
Mixtures
Do not add pure antifreeze to the cooling system in
order to adjust the concentration of antifreeze. Refer
to Operation and Maintenance Manual, “Refill
Capacities” for the correct procedure. The pure
antifreeze increases the concentration of antifreeze in
the cooling system. The increased concentration
increases the concentration of dissolved solids and
undissolved chemical inhibitors in the cooling system.
The antifreeze mixture must consist of equal
quantities of antifreeze and clean soft water. The
corrosion inhibitor in the antifreeze will be diluted if a
concentration of less than 50% of antifreeze is used.
Concentrations of more than 50% of antifreeze may
have the adverse effect on the performance of the
coolant.
Checking the Filler Cap
One cause for a pressure loss in the cooling system
can be a faulty seal on the radiator pressure cap.
Illustration 37
g00296067
Typical schematic of filler cap
(1) Sealing surface between the pressure cap and the radiator
UENR0617
37
This document has been printed from SPI2. NOT FOR RESALE.