Maintenance Of Major Components; Cooling System - Doosan DE12 Series Operation & Maintenance Manual

4. MAINTENANCE OF MAJOR COMPONENTS

4.1. Cooling System

This engine is water-cooling type. Heat from the combustion chamber and engine oil heat are cooled
down by coolant and radiated to the outside, resulting in the normal operation of the engine.
Looking into the cooling system, the water pumped up by the water pump circulates around the oil cooler
through the water pipe to absorb the oil heat, and then flows through the water jacket of the cylinder block
and water passage of the cylinder head to absorb the heat of the combustion chamber.
The water absorbing the oil heat and combustion chamber heat goes on to the thermostat through the
water pipe, and circulates to the water pump if water temperature is lower than the valve opening
temperature on the thermostat, while circulating to the radiator at water temperature higher than the valve
opening temperature. At the radiator, the heat absorbed in the coolant is radiated to cool down and the
coolant recirculates to the water pump.
Specification
1. Water pump
2. Thermostat
3. Cooling fan and belt
Thermostat
Water pump
Air compressor
Description
Type
Delivery
Pumping speed
Pumping back pressure
Operating temperature
Fan diameter - Number of blades
Fan belt tension
- 90 -
Water pipe
Cylinder head
Cylinder block
Oil cooler
Specification
Centrifugal type
About 350 liter/min
2,100 rpm
760 mmHg
83 ~ 95°C
ø
700 mm - 9 or
MAINTENANCE OF MAJOR COMPONENTS
EQM4001L
ø
700 mm - 8