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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