The coolant pump is sealed with a slip ring seal to the input shaft. To prevent the seal from drying out, a minor coolant leak is necessary to keep the seal lubricated.
Excess coolant from the minor leak is discharged through two leakage holes on the coolant pump. This minor leak is normal operation of the coolant pump, and it is not responsible for coolant loss.
This discharged coolant may dry and encrust the coolant pump (Figure 3).
