NUT 1B4445 - Caterpillar

Impellers and seals require periodic inspection. Impellers have a service life that is limited. The service life depends on the engine operating conditions.Inspect the components more frequently when the pump is exposed to debris, sand, or other abrasive materials. Inspect the components if the pump is operating at a differential pressure of more than 103 kPa (15 psi).Refer to Disassembly and Assembly, "Auxiliary Water Pump - Remove" to remove the auxiliary water pump. Refer to Disassembly and Assembly, "Auxiliary Water Pump - Disassemble" to disassemble the auxiliary water pump.Inspect the following components for wear or damage:
Bearings
Impeller
Seals
Wear plateIf wear or damage is found, replace the components which are worn or damaged. Use the proper repair kit for the pump.Refer to Disassembly and Assembly, "Auxiliary Water Pump - Assemble" to assemble the auxiliary water pump. Refer to Disassembly and Assembly, "Auxiliary Water Pump - Install" to install the auxiliary water pump.Water Pump Leak Detection
A small amount of weepage across the surface of the water pump seal is normal. The weepage is required to provide lubrication for this type of seal. A weep hole is provided from the pump housing to allow coolant to drain from the pump housing and not accumulate in the water seal and oil seal chamber.The following criteria is provided as a guideline to determine if the water pump should be replaced.
Table 1
Condition Result
Intermittent drip - 1 drip per second or less, for a period of 3 days: wetness, or discoloration (dried coolant) around the weep hole Do not replace the water pump. Continue to monitor the water pump and coolant level until the drip stops.
Constant stream and/or intermittent drip greater than 3 days Replace the water pump.