Series 50

Section 26.12 Defective Crankshaft Main Bearing Shells

Section 26.12
Defective Crankshaft Main Bearing Shells

To determine if defective crankshaft main bearing shells are causing low oil pressure, perform the following: ‪

  1. Check main bearing to crankshaft journal clearances; refer to "Additional Information" .
    1. If main bearing shell-to-journal clearance is within 0.040-0.151 mm (0.0016-0.006 in.), check oil pump assembly; refer to "26.13 Defective Oil Pump Assembly" .
    2. If main bearing shell-to-journal clearance is not within 0.040-0.151 mm (0.0016-0.006 in.); refer to "26.12.1 Crankshaft Main Bearing Shell Repair" .

Section 26.12.1
Crankshaft Main Bearing Shell Repair

Perform the following steps to repair crankshaft main bearing shells:‪

  1. Remove and replace defective crankshaft main bearing shells; refer to "1.9.2 Removal of Main Bearing Shell" .
  2. Verify crankshaft main bearing shells repair: refer to "26.12.1.1 Test Engine with New Crankshaft Main Bearing Shells" .
Section 26.12.1.1
Test Engine with New Crankshaft Main Bearing Shells

Perform the following to determine if repaired relief valve resolved low oil pressure:‪

  1. Install the Diagnostic Data Reader to the vehicles Display Data Line Adaptor, see Figure "Typical Display Data Line Adaptor" ; refer to OEM guidelines.
  2. Start and run engine between 1800 r/min.
  3. Visually examine the DDR for oil pressure reading.
    1. If the DDR indicates 241 kPa (35 lb/in.2 ), at 1800 r/min, shut down the engine and disconnect the DDR. No further troubleshooting is required.
    2. If the DDR indicates less than 241 kPa (35 lb/in.2 ), at 1800 r/min, shut down the engine and disconnect the DDR. Check the oil pump assembly; refer to "26.13 Defective Oil Pump Assembly" .


Series 50 Service Manual - 6SE50
Generated on 10-13-2008

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