the system (see Pressure Flushing) and repeat the
9. When the vehicle is equipped with a water heater
connected to the cooling system, flush the heater,
following the same procedure as for the radiator core.
8. If clogging of the core, indicated by low
temperature spots on core, is not reliev ed, the
10. After completing the flushing operation, clean
out the radiator ov erflow pipe; inspect the water
radiator core must be remov ed for mechanical
pump; clean the thermostat and the radiator cap
cleaning. Mechanical cleaning requires remov al of
control v alves. Check the thermostat for proper
the upper and lower tanks, and rodding out the
operation before installation.
accumulated rust and scale from the water
passages of the core.
11. Blow insects and dirt from the radiator core air
passages, using water, if necessary, to soften
PRE SSU RE FLUSH ING.
1. Disconnect the upper radiator hose which
CO MPO N ENT IN SP ECT IO N .
connects the radiator core to the engine water
outlet, and remov e the thermostat from the engine
Rad ia t o r.
1. Top and Bottom Tank. Look for leaks,
2. Clamp a conv enient length of hose to the
particularly where the tank is soldered to the core.
radiator core outlet opening, and attach another
Vibration and puIsation from pressure can fatigue
suitable length of hose to the radiator inlet opening
to carry away the flushing stream.
2. Filler Neck. The sealing seat must be smooth
3. Connect the flushing gun to compressed air
and clean. Cams on filler neck must not be bent or
and water pressure, and clamp the gun nozzle to
worn so as to allow a loose fitting cap. Ensure the
the hose attached to the radiator outlet opening.
ov erflow tube is not plugged.
4. With the radiator cap on tight, fill the core with
3. Radiator Cap. This is the pressure-setting type.
water. Turn on air pressure in short blasts to
Its purpose is to hold the cooling system under a
prev ent core damage.
slight pressure, increasing the boiling point of the
cooling solution and prev enting loss of solution due
5. Continue filling the radiator with water and
to ev aporation and ov erflow.
applying air pressure as abov e until the water
comes out clear.
The cap has a spring-loaded v alve, the seat of
which is below the ov erflow pipe in the filler neck.
6. Clamp the flushing gun nozzle firmly to a hose
This prev ents the escape of air or liquid while the
attached securely to the engine water outlet opening.
cap is in position. W hen the cooling system
Fill the engine block with water, partly covering the
pressure reaches a predetermined point, the cap
water inlet opening to permit complete filling.
valv e opens and will again close when the
pressure falls below the predetermined point.
7. Turn on compressed air to blow out water and
loose sediment. Continue filling with water and blowing
When removing the pressure type cap from the radiator,
out with air until flushing stream comes out clear.
perform the operation in two steps. Loosening the cap to
its first notch raises the valve from the gasket and
8. For badly clogged water jackets that do not
releases the pressure through the overflow pipe. In the
respond to regular pressure flushing, remov e the
first stage position of the cap, it should be possible to
engine cylinder head and core hole plugs, and with
depress the cap approximately 0.125-inch (3.175 mm).
a suitable length of small copper tubing attached to
The prongs on the cap can be bent to adjust this
the flushing gun nozzle, flush the water jackets
condition. Care must be taken that the cap is not too
through the openings.
loose as this would prevent proper sealing.