Ingersoll-Rand Thermo King SGCM 4000, Maintenance Manual

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Engine Maintenance
127
Engine Cooling System
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,
circulates it through the cylinder block and head and returns it to the radiator. A thermostat mounted in the
water outlet box 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 50 percent permanent type antifreeze
concentrate and 50 percent water mixture 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.
Figure 51: Cooling Circuit Diagram