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SERIES 50 FAULTY WATER PUMP

To determine if a faulty water pump is causing high engine coolant temperature, perform the following: ‪

  1. Remove the water pump (gear case mounted); refer to Section .
  2. Turn the water pump over and install J 35687 , water pump impeller slip and lash tester, into the tapped holes provided in the impeller; see Figure 20485 .

    Measuring Water Pump Drive Gear Run-Out

  3. Clamp the water pump drive gear in a vise, with the impeller facing up. Use soft jaws to prevent damage to the gear teeth.
  4. Using a 1/2 in. drive torque wrench in the hole provided in the center of the slip-lash tester, apply 68 Nm (50 lbft) torque in either direction. The impeller must withstand 68 Nm (50 lbft) torque without slipping.
    1. If the torque 68 Nm (50 lbft) is satisfied without the impeller slipping, check combustion gases in coolant; refer to Section .
    2. If the torque 68 Nm (50 lbft) is not satisfied and the impeller is slipping; refer to Section .

Water Pump Impeller Replacement

Perform the following steps to replace water pump impeller: ‪

  1. Disassemble the water pump and replace worn or damaged impeller; refer to Section for (gear case mounted).
  2. Reassemble the water pump with new components as necessary; refer to Section for (gear case mounted).
Test Engine with Repaired Water Pump

Perform the following to determine if thermo-modulated fan replacement resolved high engine coolant temperature: ‪

  1. Start and run the engine.
  2. Run the engine through its operating range with no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
    1. If the engine coolant temperature is 88-96C (190-210F), no further troubleshooting is required. Shut the engine down.
    2. If the engine coolant temperature is not 88-96C (190-210F), shut the engine down. Check combustion gases in coolant; refer to Section .