Section 05: COOLING SYSTEM
10 X3-45 Commuter PA1593 DOB 2400-2489 Section 05 Updated Sept.2016
Dispose of spent fluids in an environmentally
responsible manner according to regulations in
effect in your area.
COOLING SYSTEM CAPACITY
(approximation)
Includes heating system: 24 US gal (91 liters)
8.1 COOLING SYSTEM DESCALERS
If the engine overheats and the fan belt tension,
coolant level and thermostat operation have
been found to be satisfactory, it may be
necessary to de-scale and flush the entire
cooling system.
Remove scale formation by using a reputable
and safe de-scaling solvent. Immediately after
using the de-scaling solvent, neutralize with a
neutralizing agent. It is important that product
directions be thoroughly read and followed.
After using the solvent and neutralizer, fully
drain the system, and then reverse flush the
engine and radiator (see "Reverse Flushing" in
this section) before filling the system with
coolant solution.
8.2 REVERSE FLUSHING
After the engine and radiator have been
thoroughly de-scaled, they should be reverse-
flushed. The water pump should be removed
and the radiator and engine reverse-flushed
separately to prevent dirt and scale deposits
from clogging the radiator tubes or being forced
through the pump. Reverse flushing is
accomplished by hot water, under pressure,
being forced through the cooling system in a
direction opposite to the normal flow of coolant,
loosening and forcing deposits out.
The radiator is reverse flushed as follows:
1. Remove the radiator inlet and outlet hoses
and replace existing radiator cap with a new
one.
2. Attach a hose to the top of the radiator to
lead water away from the engine.
3. Attach a hose at the bottom of the radiator
and insert a flushing gun in the hose.
4. Connect the water hose of the gun to the
water outlet and the air hose to the
compressed air outlet.
5. Turn on the water and when the radiator is
full, turn on the air in short blasts, allowing
the radiator to fill between blasts.
NOTE
Apply air gradually. Do not exert more than
138 kPa (20 psi) air pressure. Too great a
pressure may rupture a radiator tube.
6. Continue flushing until only clean water is
expelled from the radiator.
The cylinder block and cylinder head water
passages are reverse flushed as follows:
1. Remove the thermostats and the water
pump.
2. Attach a hose to the water inlet of oil cooler
housing to drain water away from engine.
3. Attach a hose to the water outlet at the top of
the cylinder head (thermostat housing) and
insert the flushing gun in the hose.
4. Turn on the water until the jackets are filled,
and then turn on the air in short blasts. Allow
jackets to fill with water between air blasts.
5. Continue flushing until the water from the
engine runs clean.
If scale deposits in the radiator cannot be
removed by chemical cleaners or reverse
flushing as outlined above, it may be necessary
to remove the upper tank and rod out the
individual radiator tubes with flat steel rods.
Circulate the water through the radiator core
from the bottom to the top during this operation.
9. SPIN-ON COOLANT FILTER
The engine cooling system filter is used to filter
out impurities such as scale or sand from the
coolant and it also eliminates the process of
adding inhibitors to the antifreeze/water solution.
The filter is mounted onto the cooling fan drive
mechanism aluminum casting (Fig. 9).
To replace a filter:
1. Close the filter shutoff cock on the filter
mounting head and unscrew the old filter
from mounting.
WARNING
Failure to relieve cooling system pressure
may result in personal injury.
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