3. Attach a hose to the water outlet at tile top of the cylinder block and insert the flushing gun in the hose.
4. Turn on the water and, when the water jackets are filled, turn on the air in short blasts, allowing the engine 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 water through
the radiator core from the bottom to the top during this operation.
Miscellaneous Cooling System Checks
In addition to the above cleaning procedures, the other components of the cooling system should be checked periodically
to keep the engine operating at peak efficiency. The thermostat and the radiator pressure cap should be checked and
replaced, if found defective. The cooling system hoses should be inspected and any hose that feels abnormally hard or
soft should be replaced immediately.
Also, check the hose clamps to make sure they are tight. All external leaks should be corrected as soon as detected. The
fan belt must be adjusted to provide the proper tension, and the fan shroud must be tight against the radiator core to
prevent re-circulation of air which may lower cooling efficiency.
A centrifugal-type water pump is mounted on top of the engine oil cooler housing, either on the right-hand or left-hand side
of the engine, depending upon the engine model and rotation. It circulates the coolant through the cooling system.
The pump is belt driven, by either the camshaft or balance shaft (In-line engines) or by one of the camshafts (V-type
An impeller is pressed onto one end of the water pump shaft, and a water pump drive pulley is pressed onto the opposite
end. The pump shaft is supported on a sealed double-row combination radial and thrust ball bearing. Coolant is
prevented from creeping along the shaft toward the bearing by a seal. The shaft and bearing constitute an assembly and
are serviced as such, since the shaft serves as the inner race of the ball bearing.
The sealed water pump shaft ball bearing is filled with lubricant when assembled. No further lubrication is required.
Contact an authorized Detroit Diesel Allison Service Outlet if more information is needed.