Lexus NX: On-vehicle Inspection

HINT:

• Water Pump Construction Evaporation Port and Drain Plug:

  *1	Evaporation Port	*2	Mechanical Seal
  *3	Fluid Catch Pocket	*4	Drain Plug
  *a	Typical Water Pump Assembly	-	-

• Water Pump Mechanical Seal
  • The water pump shaft is sealed by a mechanical type seal. Mechanical Seal Components:

    *1	Spring: Applies pressure to the seal ring to ensure the seal ring and mating ring are in constant contact.	*2	Seal Ring: Stationary sealing member in the water pump housing, held in place by the cartridge.
    *3	Mating Ring: Rotates with the water pump shaft and provides sealing surface for the seal ring.	*4	Cartridge: Locates the seal ring and bellows in the water pump housing.
    *5	Bellows: Seals the cartridge and the seal ring.	-	-

• Temporary Leaks
  • As the water pump assembly rotates, a small amount of engine coolant is discharged to cool and lubricate the sliding surface of the mechanical seal and evaporates.

    (Water pump replacement is not necessary)

  • If debris becomes lodged between the mating ring and seal ring a small gap is formed. This allows coolant to bypass the mechanical seal, flow into the fluid catch pocket, and drain out of the weep hole. This condition is temporary and will no longer be present once the debris breaks up or works its way out of the seal.

    (Water pump replacement is not necessary)

    Examples (Dry Coolant Residue): Examples (Wet Coolant Residue/Drips): Debris in Mechanical Seal:

    *1	Mating Ring	*2	Seal Ring: gap formed by debris
    *3	Spring	*4	Cartridge
    *5	Bellows	*6	Housing Side
    *7	Impeller Side	-	-