PLATE AS 4648977 - Caterpillar

Introduction
This engine has a pressure type cooling system. A pressure type cooling system gives two advantages:
The pressure type cooling system can operate safely at a higher temperature than the boiling point of water at a range of atmospheric pressures.
The pressure type cooling system prevents cavitation in the water pump.Cavitation is the sudden generation of low-pressure bubbles in liquids by mechanical forces. The generation of an air or steam pocket is much more difficult in a pressure type cooling system.Regular inspections of the cooling system should be made in order to identify problems before damage can occur. Visually inspect the cooling system before tests are made with the test equipment. Inspection Procedure
Visual Inspection Of The Cooling System
Check the coolant level in the cooling system.
Look for leaks in the system. Note: A small amount of coolant leakage across the surface of the water pump seals is normal. This leakage is required in order to provide lubrication for this type of seal. A hole is provided in the water pump housing in order to allow this coolant/seal lubricant to drain from the pump housing. Intermittent leakage of small amounts of coolant from this hole is not an indication of water pump seal failure.
Inspect the radiator for bent fins and other restriction to the flow of air through the radiator.
Inspect the drive belt for the fan.
Inspect the blades of the fan for damage.
Look for air or combustion gas in the cooling system.
Inspect the radiator cap for damage. The sealing surface must be clean.
Look for large amounts of dirt in the radiator core. Look for large amounts of dirt on the engine.
Shrouds that are loose or missing cause poor air flow for cooling.