Skip to main content

MBE 4000 COOLANT PUMP

Perform the following procedures for removal and installation of the coolant pump. ‪

Coolant Pump Removal

Remove the coolant pump as follows: ‪

HOT COOLANT

To avoid scalding from the expulsion of hot coolant, never remove the cooling system pressure cap while the engine is at operating temperature. Wear adequate protective clothing (face shield, rubber gloves, apron, and boots). Remove the cap slowly to relieve pressure.

  1. Drain the coolant from the engine. Refer to section .
  2. Remove the fan.
  3. Release the tension on the main drive belt and the fan belt and set the belts aside
  4. Remove the fan support from the cylinder block. See Figure 42159 . Refer to section .

    1. Coolant Pump Pulley Mounting Bolt ‪

    6. Fan Support ‪

    2. Coolant Pump Pulley ‪

    7. Fan Pulley ‪

    3. Coolant Pump Assembly ‪

    8. Pump Mounting Bolt ‪

    4. Gasket ‪

    9. Fan Support Mounting Bolt ‪

    5. Cylinder Block ‪

    Fan Support and Coolant Pump Removal

  5. Remove the coolant pump pulley from the coolant pump housing.
  6. Remove the mounting bolts from the front idler and tensioner support. Slide the support to the right-hand side of the engine. See Figure 42160 .
  7. Remove the upper alternator mounting bolt, loosening the alternator enough to tilt it out of the way.
  8. Remove the inlet pipe from the coolant pump housing. See Figure 42160 .

    1. Lower Coolant Tube ‪

    5. Coolant Pump Housing ‪

    2. Inlet Pipe Mounting Bolt ‪

    6. Front Idler and Tensioner Support ‪

    3. Inlet Pipe ‪

    7. Coolant Pump Support Mounting Bolt ‪

    4. Inlet Pipe Gasket ‪

    8. Upper Coolant Tube ‪

    Coolant Pump Inlet Pipe (exploded view)

    Note: Catch any coolant that runs out of the inlet pipe or coolant pump in a suitable container.

  9. Remove the upper coolant tube from the thermostat housing.
  10. Remove the coolant pump from the cylinder block. Discard the gasket.
  11. On both the coolant pump and the cylinder block, clean the sealing surfaces (where the gasket was attached) of any adhering bits of gasket material.
  12. Remove the thermostat housing from the coolant pump.

Coolant Pump Disassembly

Disassemble the coolant pump unit as follows: ‪

  1. Remove the coolant pump from the engine. Refer to section .
  2. Using a puller, pull the coolant pump hub away from the bearing. See Figure 42220 .

    1. Puller ‪

    3. Coolant Pump Housing ‪

    2. Hub ‪

    Pulling the Hub

  3. Remove the snap ring from the coolant pump housing. See Figure 42221 .

    1. Hub ‪

    4. Coolant Pump Housing ‪

    2. Snap Ring ‪

    5. Sleeve Seal ‪

    3. Drive Shaft and Bearing Assembly ‪

    6. Impeller ‪

    Coolant Pump Assembly (exploded view)

  4. Using an appropriate drift, press the drive shaft and bearing assembly out of the impeller and through the coolant pump housing. This frees the impeller from the housing. See Figure 42222 .

    1. Sleeve Seal ‪

    4. Receptacle ‪

    2. Drift ‪

    5. Drive Shaft and Bearing Assembly ‪

    3. Impeller ‪

    Removing the Drive Shaft

  5. Remove the sleeve seal from the coolant pump housing.
Coolant Pump Inspection

Inspect the coolant pump unit as follows: ‪

  1. Check all coolant pump components for signs of damage. Replace any damaged components.
  2. Measure the following wear dimensions. Replace any component that is not within tolerance as Listed in Table .

    Description

    Wear Dimensions, mm (inch)

    Drive Shaft Diameter (at the hub) ‪

    25.048-25.061 (0.9861-0.9867) ‪

    Hub Inside Diameter ‪

    24.995-25.008 (0.9841-0.9846) ‪

    Bearing Outside Diameter ‪

    54.981-54.994 (2.1646-2.1651) ‪

    Bearing Housing Diameter ‪

    54.930-54.960 (2.1626-2.1638) ‪

    Drive Shaft Diameter (at the impeller) ‪

    15.045-15.056 (0.5923-0.5928) ‪

    Impeller Inside Diameter ‪

    15.000-15.018 (0.5906-0.5913) ‪

    Impeller Outside Diameter ‪

    124-125 (4.88-4.92) ‪

    Impeller - Maximum Out-Of-Round ‪

    0.15 (0.0059) ‪

    Coolant Pump Assembly Wear Dimensions

Coolant Pump Assembly

Assemble the coolant pump unit as follows: ‪

  1. Press the drive shaft and bearing assembly into the coolant pump housing. See Figure 42223 .

    1. Drive Shaft ‪

    2. Coolant Pump Housing ‪

    Installing the Drive Shaft

    1. Place the coolant pump housing in a press.
    2. Place the coolant pump pressure piece, (J 45388 of 355 589 02 43 00) , over the outer bearing race.
    3. Place the receptacle, (J 45388 of 355 589 02 43 00) , under the coolant pump housing.
    4. NOTICE:

      To prevent damage to the drive shaft and bearing assembly, press only on the outer bearing race.

    5. Press the outer race of the bearing into the coolant pump housing.
  2. Secure the bearing in place with the snap ring.

    PERSONAL INJURY

    To avoid injury from hot surfaces, wear protective gloves, or allow engine to cool before removing any component.

  3. Press the hub onto the drive shaft and bearing assembly.
    1. Heat the hub to 175F (80C).

      NOTICE:

      To prevent damage to the bearing, make sure the drive shaft is supported evenly before pressing on the hub.

    2. Press the hub onto the drive shaft, while holding the bearing and drive shaft assembly to prevent it from turning. Make sure the hub is flush with the end of the drive shaft.
  4. Using the coolant pump bearing drift (352 589 08 15 00) , press the sleeve seal into the coolant pump housing. See Figure 42224 .

    1. Sleeve Seal ‪

    3. Coolant Pump Housing ‪

    2. Drive Shaft ‪

    Installing the Sleeve Seal

  5. Press the impeller onto the drive shaft and bearing assembly. See Figure 42225 .

    1. Impeller ‪

    3. Sleeve Seal ‪

    2. Drive Shaft ‪

    Pressing in the Impeller

    Note: Secure both the drive shaft and hub to prevent them from turning while the impeller is being installed.

  6. Measure the gap between the impeller and the coolant pump housing. This gap, listed in Table , must be more than 0.6 mm (0.023 inch) and less than 1.0 mm (0.039 inch). See Figure 42226 .

    Description

    mm (inch)

    Gap Between the Impeller and the Coolant Pump Housing ‪

    0.6-1.0 (0.023-0.039) ‪

    Coolant Pump Assembly, Critical Dimension

    1. Impeller ‪

    2. Coolant Pump Housing ‪

    Gap Between the Impeller and the Housing

  7. Rotate the coolant pump drive shaft to make sure it moves easily and freely.
  8. Install the coolant pump on the engine.

Coolant Pump Installation

Install the coolant pump as follows: ‪

  1. Install the coolant pump on the cylinder block. Install a new gasket. Tighten the mounting bolts 30 Nm (22 lbft).
  2. Connect the inlet pipe to the coolant pump housing, as removed. Install a new gasket on the mating surface between the inlet pipe and the coolant pump housing. Tighten the inlet pipe mounting bolts 50 Nm (37 lbft).
  3. Tilt the alternator back into the correct position. Install the upper alternator mounting bolt and restore the alternator to operating condition.
  4. Install the upper coolant tube onto the thermostat housing.
  5. Install the coolant pump pulley and the mounting bolts attaching the coolant pump pulley to the coolant pump. Tighten the bolts 25 Nm (18 lbft).
  6. Move the front idler and tensioner support back into place on the cylinder block. Tighten the mounting bolts 60 Nm (44 lbft).
  7. Install the fan support on the cylinder block.
  8. Release the belt tensioners for the main drive and fan belts. Route the two belts around their pulleys and restore the belt tension.
  9. Install the fan.
  10. Fill the engine with coolant, as removed, and check for leaks.