KEY-WOODRUFF 1B8704 - Caterpillar

Engine:
C4.4 (S/N: MMC1-UP; XYC1-UP; XYD1-UP; N4E1-UP; L1K1-UP; S1M1-UP)
Industrial Engine:
3054C (S/N: 3347-UP)
3054E (S/N: 304336-UP)
During normal operation, the seal on the shaft in the water pump will allow a small amount of coolant and vapor to pass over the seal into a chamber area. The chamber area allows coolant that is expelled over the seal to evaporate. The vapor will exit out of the weep hole. In certain environmental conditions and operating conditions, not all of the liquid will be evaporated. If the coolant is unable to evaporate from the chamber the coolant may be expelled from the weep hole. A small amount of coolant from the weep hole is not a failure of the seal. In normal pump operation, a small loss of coolant from the weep hole will occur. If there is a failure of the seal on the shaft of the water pump a significant amount of coolant will be lost through the weep hole.The most common cause of coolant leaks from the weep hole is due to the water pump seal damage. The seal will melt when the water pump has insufficient coolant around the seal. The following situations can cause cooling fluid starvation problems around the seal:
Low coolant level
Inadequate maintenance
Air that has not been removed from the coolant system on initial fill
Leaks within the cooling system
Boiling of the coolantCooling fluid boiling will introduce air pockets into the coolant system. Boiling of the coolant can be caused by the following situations:
Pressure leak from the cooling system
Incorrect Glycol concentration
Restricted air flow around the cooling system
Restricted cooling fluid flow through the thermostat