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SERIES 638 OIL PUMP

The lubrication system has a rotor-type oil pump located in the front of the crankcase and driven by a gear directly meshing with the crankshaft gear. ‪

Oil is directed through an oil pressure valve to the full-flow filter and through appropriate oil passages machined in the crankcase to the main bearing carriers, camshaft bearings, and to the turbocharger. ‪

Oil jets located on the bearing carriers lubricate and cool piston pins, connecting rod-to-piston, and the internal area of the pistons. An external oil line allows proper lubrication of the rocker arms. If the oil filter is clogged, a bypass valve located in the oil filter cartridge will allow the oil to circulate through the engine. ‪

Replacement of Oil Pump

To determine if replacement of the oil pump is necessary, perform the following procedure. See Figure 28575 . ‪

Flowchart for Repair or Replacement of Oil Pump

Removal of Oil Pump

Remove the oil pump as follows: ‪

  1. Remove front cover. Refer to section .
  2. Remove three Allen head retaining bolts from oil pump. See Figure 28401 .

    1.Injection Pump Gear ‪

    4.Crankshaft Gear ‪

    2.Camshaft Gear ‪

    5.Vacuum Pump Gear ‪

    3.Oil Pump Gear ‪

    Oil Pump Location

  3. Remove oil pump from cylinder block.
Cleaning of Oil Pump

Clean the oil pump as follows: ‪

  1. Clean oil pump and related parts with 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. ‪

  2. Dry oil pump and related parts with compressed air.
Inspection of Oil Pump

Inspect the oil pump as follows: ‪

  1. Visually check the oil pump rotors for scored, gulled, or pitted surfaces.
    1. If the oil pump rotors are scored, gulled, or pitted, replace the component. Refer to section .
    2. If the oil pump rotors are not scored, gulled, or pitted, reuse the component. Refer to section .
  2. Measure the clearance between the rotors and the oil pump housing.
    1. If the clearance between the rotors and the oil pump housing is not within 0.130 mm (0.0051 in.), replace the component. Refer to section .
    2. If the clearance between the rotors and the oil pump housing is within 0.130 mm (0.0051 in.), reuse the component. Refer to section .

Installation of Oil Pump

Install the oil pump as follows: ‪

  1. Install the oil pump to the cylinder block using three Allen screws. Torque to 27-28 N m (20-21 lb ft). See Figure 28401 .

    1.Injection Pump Gear ‪

    4.Crankshaft Gear ‪

    2.Camshaft Gear ‪

    5.Vacuum Pump Gear ‪

    3.Oil Pump Gear ‪

    Oil Pump Location

  2. Install the front cover. Refer to section .
  3. Run the engine to verify repairs.