BASE 4N9774 - Caterpillar

Cooling systems that are not regularly inspected are the cause for increased engine temperatures. Make a visual inspection of the cooling system before any tests are performed.
Personal injury can result from escaping fluid under pressure.If a pressure indication is shown on the indicator, push the release valve in order to relieve pressure before removing any hose from the radiator.
Check the coolant level in the cooling system. Refer to Operation and Maintenance Manual, "Cooling System Coolant Level - Check".
Check the quality of the coolant. The coolant should have the following properties:
Color that is similar to new coolant
Odor that is similar to new coolant
Free from dirt and debrisIf the coolant does not have these properties, drain the system and flush the system. Refill the cooling system with the correct mixture of water, antifreeze, and coolant conditioner. Refer to the Operation and Maintenance Manual for your engine in order to obtain coolant recommendations.
Look for leaks in the system.Note: A small amount of weepage across the surface of the water pump seals is normal. This weepage is required to provide lubrication for this type of seal. A weep hole is provided in the water pump housing to allow coolant weepage to drain from the pump housing and not accumulate in the water seal and oil seal chamber.The following coolant leakage criteria is provided as a guideline to determine if the water pump should be replaced.
Intermittent drip (1 drip per second or less) for a period of 3 days, wetness, or discoloration (dried coolant) around the weep hole.Action: Do not replace pump. Continue to monitor water pump and coolant level till dripping stops
Constant stream or/and intermittent drip for a period greater than 3 days.Action: Replace pump
Ensure that the air flow through the radiator does not have a restriction. Look for bent core fins between the folded cores of the radiator. Also, look for debris between the folded cores of the radiator.
Inspect the drive belts for the fan.
Check for damage to the fan blades.
Look for air or combustion gas in the cooling system.
Inspect the filler cap, and check the surface that seals the filler cap. This surface must be clean.