Thermo King UT-1200, Manual

Page: 92 / 169

Engine Maintenance
92
Engine Cooling System
General Description
The engine employs a closed, circulating type,
pressurized cooling system. Correct engine
temperatures are controlled and maintained by a
radiator, fan and thermostat. The coolant is
circulated through the system by a belt-driven
centrifugal pump. The pump draws the coolant
from the side of the radiator (large header),
circulates it through the cylinder block and head,
then back to the radiator. A thermostat mounted in
the water outlet from the cylinder head to the
radiator automatically maintains coolant
temperature within the specified temperature
range.
All water-cooled engines are shipped from the
factory with a mixture of 50 percent permanent
type antifreeze concentrate and 50 percent water
in the engine cooling system.
This provides the following:
1. Prevents freezing down to -30 F (-34 C).
2. Retards rust and mineral scale that can cause
engine overheating.
3. Retards corrosion (acid) that can attack
accumulator tanks, water tubes, radiators and
core plugs.
4. Provides lubrication for the water pump seal.
1
2
4
3
5
6
1. Radiator 4. Expansion Tank
2. Water Temperature Sensor 5. Coolant Level Sensor
3. Engine 6. Bleed Line
Figure 161: Engine Cooling System Components