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SERIES 638 WATER MANIFOLD

Coolant is circulated by the water pump located at the front of the crankcase and is belt driven. Coolant flows inside the block around the liners and through internal passages and rises to the cylinder heads. The coolant is then circulated through the water manifold which collects the water at the outlets from the cylinder head. ‪

Repair or Replacement of Water Manifold

To determine if repair is possible or replacement of the water manifold is necessary perform the following procedure. See Figure 27225 . ‪

Flowchart for Repair or Replacement of Water Manifold

Removal of Water Manifold

To remove the water manifold, perform the following: ‪

Do not remove the pressure control cap from the radiator or attempt to drain the coolant until the engine has cooled. Once the engine has cooled, use extreme caution when removing the cap. The sudden release of pressure from a heated cooling system can result in a loss of coolant and possible personal injury (scalding, eye injury, etc.) from the hot liquid. ‪

  1. Drain the cooling system.
  2. Disconnect water manifold to water pump hose.
  3. Remove upper radiator hose from water manifold.
  4. Disconnect heater hose from water manifold.
  5. Disconnect air bleed hose from water pump.
  6. Remove twelve water manifold bolts from cylinder block.
  7. Remove water manifold and discard gasket.
  8. Remove four water manifold nuts and separate manifold. Discard gasket.
  9. Remove thermostat, if necessary. Refer to section .
Cleaning of Water Manifold

To clean water manifold, perform the following: ‪

  1. Remove loose gasket material from the cylinder head and water manifold surfaces.
  2. Wash the water manifold in clean fuel oil.

    To avoid personal injury when blow drying, wear adequate eye protection (safety glasses or face plate) and do not exceed 276 kPa (40 lb/in. 2 ) air pressure. ‪

  3. Blow dry with compressed air.
Inspection of Water Manifold

Inspect water manifold as follows: ‪

  1. Visually check the water manifold for chips and cracks.
    1. If damage is found, replace the water manifold. Refer to section .
    2. If no damage is found, proceed with step of inspection.
  2. Measure the water manifold for distortion.
    1. If distortion is found, reface all flanges to restore complete face contact with cylinder head sealing surface. Refer to section .
    2. If no distortion is found, proceed with step of inspection.
  3. Visually check water manifold threads for damage.
    1. If damage is found, replace the water manifold. Refer to section .
    2. If no damage is found, reuse the water manifold. Refer to section .

Installation of Water Manifold

Install water manifold as follows: ‪

  1. Install thermostat, if removed. Refer to section .
  2. Assemble the water manifold. Torque nuts to 9-12 N m (7-9 lb ft).
  3. Install water manifold and new gasket to the cylinder head with the twelve bolts. Torque bolts to 10-13 N m (7-10 lb ft).
  4. Connect air bleed hose to the water pump.
  5. Connect heater hose to the water manifold.
  6. Connect upper radiator hose to the water manifold.
  7. Connect water pump hoses to the water pump manifold.
  8. Fill the cooling system.
  9. Run the engine to verify repair.