Engine Systems
Raw water pumps are drained by loosening the cover
de-scaling solutions to clean the cooling system. A
attaching screws and tapping the cover- gently to
hard, mineral laden water should be made soft by
using water softener chemicals before it is poured into
loosen it. After the water has drained, tighten the
screws.
the cooling system. These water softeners modify the
minerals in the water and greatly reduce or eliminate
the formation of scale.
Flushing Cooling System
Start the engine and. after the normal operating
temperature has been reached, allowing the coolant to
The cooling system should be flushed each spring and
expand to its maximum. check the coolant level. The
fall. The flushing operation cleans the system of
coolant level should he within 2" of the top of the
antifreeze solution in the spring and removes the
filler neck.
summer rust inhibitor in the fall, preparing the
cooling system for a new solution. The flushing
Should a daily loss of coolant be observed. and there
operation should be performed as follows:
are no apparent leaks, there is a possibility of gases
leaking past the cylinder head water seal rings into the
1. Drain the previous season's solution from the
cooling system. The presence of air or gases in the
engine.
cooling system may be detected by connecting a
rubber tube from the overflow pipe to a water
2. Refill the cooling system with soft clean water. If the
container. Bubbles in the water in the container during
engine is hot, fill slowly to prevent rapid cooling and
engine operation will indicate this leakage. Another
distortion of the engine castings.
method for observing air in the cooling system is by
inserting a transparent tube in the water outlet line.
3. Start the engine and operate it for 15 minutes to
circulate the water thoroughly.
4. Drain the cooling system completely.
Drain Cooling System
5. Refill the system with the solution required for the
The engine coolant is drained by opening the cylinder
coming season.
block and radiator (heat exchanger) drain cocks and
removing the cooling system filler cap. The removal of
the cooling system filler cap permits air to enter the
cooling passages and the coolant to drain completely
Cooling System Cleaners
from the system.
If the engine overheats, and the fan belt tension and
water level have been found to be satisfactory, clean
Drain cocks are located on each side of the cylinder
and flush the entire cooling system. Remove scale
block at both the front and rear of the engine. The
formation by using a reputable and safe de-scaling
drain cocks at the rear of the engine are below the
solvent. Immediately after using the de-scaling
exhaust manifold. The front surface of the cylinder
solvent, neutralize the system with the neutralizer. It is
block has drain cocks on each side above the engine
important that the directions printed on the container
front cover.
of the de-scaler be thoroughly read and followed.
In addition to the drains on the block, the oil cooler
After the solvent and neutralizer have been used,
housing has a drain cock at the extreme bottom.
completely drain the engine and radiator and reverse-
Radiators and other components that do not have a
flush before filling the system.
drain cock are drained through the oil cooler housing
drain cock.
To ensure that all of the coolant is drained completely
Reverse-Flushing
from a unit, all cooling system drains should be
opened. Should any entrapped water in the cylinder
After the engine and radiator have been thoroughly
block or radiator freeze, it will expand and may cause
cleaned, they should be reverse-flushed. The water
damage. When freezing weather is expected, drain all
pump should be removed and the radiator and engine
units not adequately protected by antifreeze. Leave all
reverse-flushed separately to prevent dirt and scale
drain cocks open until refilling the cooling system.
deposits clogging the radiator tubes or being forced
through the pump. Reverse -flushing is accomplished
Marine engine exhaust manifolds are cooled by the
by hot water, under air pressure, being forced through
same coolant used in the engine. Whenever the engine
the cooling system in a direction opposite to the
cooling system is drained, open the exhaust manifold
normal flow of coolant, loosening and forcing scale
drain cocks.
deposits out.
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