Doosan DX140LC, Operation And Maintenance Manual

Page: 260 / 297

OP000599 Inspection, Maintenance and Adjustment
4-76
ENGINE COOLING SYSTEM
GENERAL
Keeping an engine's cooling system in peak operating condition,
can have many benefits to keeping a machine in good operating
condition. A properly functioning cooling system will; improve
fuel efficiency, reduce engine wear, and extend component life.
Always use distilled water in the radiator. Contaminants in tap
water neutralize the corrosion inhibitor components. If tap water
must be used, it should not exceed 300 ppm hardness, or
contain more than 100 ppm of either chloride or sulfate. Water
that has been treated with a water softener also contains salt
that will cause corrosion of components. Water from creeks and
stagnant pools usually contains dirt, minerals and/or organic
material that are deposited in the cooling system and impair
cooling efficiency. Distilled water is the best.
Engine overheating is often caused by bent or clogged radiator
fins. The spaces between the fins can be cleaned by use of air
or water under pressure. When straightening bent fins, use care
not to damage the tubes or break the bond between the fins and
the tubes.
Heavy duty diesel engines require a balanced mixture of water
and antifreeze. Drain and replace the mixture every year or
2,000 hours of operation, which ever comes first. This will
eliminate buildup of harmful chemicals.
Antifreeze is essential in any climate. It broadens the operating
temperature range by lowering the coolant's freezing point and
by raising its boiling point. Do not use more than 50% antifreeze
in the mixture unless additional freeze protection is required.
Never use more than 68% antifreeze under any condition.
WARNING!
Pressure at air nozzle must not exceed 30 PSI (2.1 kg/
cm
2
). Always wear goggles when using compressed air.
Do not pour cold water into radiator when engine is very
hot and water level is below the top of the tubes. Such
action could result in damage to engine cylinder heads.