Maintenance section
98
Cooling System Specifications
Coolant Information
NOTE :
The following information is generic and
valid for lift trucks.
Engine operating temperatures have increased to
improve engine efficiency. This means proper cool
ing system maintenance is especially important.
Overheating, overcooling, pitting, cavitation erosion,
cracked heads, piston seizures, and plugged
radiators are classic cooling system failures. In fact,
coolant is as important as the quality of fuel and
lubricating oil.
NOTICE
DOOSAN recommends that the coolant mixture
contain a minimum of 30% antifreeze or equivalent.
Never add coolant to an overheated engine,
engine damage can result. Allow the engine to
cool first.
All water is corrosive at engine operating
temperature. The cooling system should be
protected with a 3 to 6% concentration of liquid
supplemental coolant additive at all times,
regardless of the concentration of antifreeze.
Excessive supplemental coolant additive greater
than the recommended 6%, together with concen-
tration of antifreeze greater than 65% can cause
deposits to form and can result in radiator tube
blockage, overheating, and/or water pump seal
damage.
If the machine is to be stored in, or shipped to,
an area with freezing temperatures, the cooling
system must be protected to the lowest expected
outside (ambient) temperature.
The engine cooling system is normally protected
to –28°C (–20°F) with antifreeze, when shipped
from the factory unless special requirements are
defined.
Check the specific gravity of the coolant solution
frequently in cold weather to ensure adequate
protection.
Clean the cooling system if it is contaminated, if the
engine overheats or if foaming is observed in the
radiator.
Old coolant should be drained, the system cleaned
and new coolant added every 2000 service hours or
yearly.
Refer to topic, “Cooling System-Clean, Change” in
every 2000 service hours or yearly section.
Filling at over 20 liters (5 U.S. gallons) per minute
can cause air pockets in the cooling system.
After draining and refilling the cooling system,
operate the engine with the radiator cap removed
until the coolant reaches normal operating
temperature and the coolant level stabilizes. Add
coolant as necessary to fill the system to the proper
level.
Never operate without a thermostat in the cooling
system. Cooling system problems can arise without
a thermostat.