Series 50 – Section 26.6 Rocker Arm Shaft Plugs Missing (New or Rebuilt Engines Only)

Section 26.6
Rocker Arm Shaft Plugs Missing (New or Rebuilt Engines Only)

If engine is not new or has not been rebuilt, refer to "26.7 Restricted Oil Cooler" . ‪

To determine if a missing rocker arm shaft plugs are causing low oil pressure, perform the following: ‪

1. Remove the rocker arm cover; refer to "1.6.2 Cleaning and Removing of Two-piece Rocker Cover-Diesel Engines Only" .
2. Visually inspect the rocker arm shaft for missing or leaking shaft plugs.
   1. If the shaft plugs are present and are not leaking, check the oil cooler for restriction; refer to "26.7 Restricted Oil Cooler" .
   2. If the shaft plugs are missing; refer to "26.6.2 Missing Rocker Arm Shaft Plug Repair" .
   3. If the shaft plugs are leaking, refer to "26.6.1 Leaking Rocker Arm Shaft Plug Repair" .

Section 26.6.1
Leaking Rocker Arm Shaft Plug Repair

Perform the following steps to repair leaking rocker arm shaft plugs:‪

1. Remove damaged shaft plugs; refer to "1.3 Valve and Injector Operating Mechanism" .
2. Inspect rocker arm shaft for damage; refer to "1.3.3.1 Inspection of Rocker Arm Assemblies and Camshaft Lobes" . If damage is found, replace the rocker arm shaft; refer to "1.3.2 Removal of Rocker Arm Assembly" .
3. Install new shaft plugs; refer to "1.3.4 Installation of Rocker Arm Shaft Assembly" .

   Note: Shaft plug must be installed 1.0-1.3 mm (0.040-0.050 in.) below surface using J 36236 .

4. Install rocker arm cover; refer to "1.6.7 Installation of the Two-piece Rocker Cover Base" .
5. Verify repair made to the rocker shaft plugs; refer to "26.6.2.1 Test Engine with Repaired Rocker Shaft Plugs" .

Section 26.6.2
Missing Rocker Arm Shaft Plug Repair

Perform the following steps to repair missing rocker arm shaft plugs:‪

1. Inspect rocker arm shaft for damage; refer to "1.3.3.1 Inspection of Rocker Arm Assemblies and Camshaft Lobes" . If damage is found, replace the rocker arm shaft; refer to "1.3.2 Removal of Rocker Arm Assembly" .
2. Install new shaft plugs; refer to "1.3.4 Installation of Rocker Arm Shaft Assembly" .

   Note: Shaft plug must be installed 1.0-1.3 mm (0.040-0.050 in.) below surface using J 36236 .

3. Install rocker arm cover; refer to "1.6.7 Installation of the Two-piece Rocker Cover Base" .
4. Verify repair made to the rocker shaft plugs; refer to "26.6.2.1 Test Engine with Repaired Rocker Shaft Plugs" .

Section 26.6.2.1
Test Engine with Repaired Rocker Shaft Plugs

Perform the following to determine if repaired rocker shaft plugs 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 speed at 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 cooler for restriction; refer to "26.7 Restricted Oil Cooler" .