Series 50 – Section 26.10 Defective Pressure Relief Valve

Section 26.10
Defective Pressure Relief Valve

To determine if a defective pressure relief valve is causing low oil pressure, perform the following: ‪

1. Remove the pressure relief valve; refer to "3.4.2 Cleaning and Removal of Oil Pressure Relief Valve" .
2. Inspect the oil pressure relief valve; refer to "3.4.3.1 Inspection of Oil Pressure Relief Valve" .
   1. If the regulator valve moves freely in the valve body. Reinstall the oil pressure relief valve; refer to "3.4.5 Installation of Oil Pressure Relief Valve" , check the pickup tube and screen assembly for defects; refer to "26.11 Defective Pickup Screen Tube and Screen Assembly" .
   2. If the regulator valve will not move freely in the valve body, refer to "26.10.1 Pressure Relief Valve Repair" .

Section 26.10.1
Pressure Relief Valve Repair

Perform the following steps to repair the pressure relief valve:‪

1. Disassemble the pressure relief valve and replace damaged components; refer to "3.4.1 Repair or Replacement of Oil Pressure Relief Valve" .
2. Assemble and install the pressure regulator valve; refer to "3.4.4 Assembly of Oil Pressure Relief Valve" .
3. Verify repair of the regulator valve; refer to "26.10.1.1 Test Engine with Repaired Relief Valve" .

Section 26.10.1.1
Test Engine with Repaired Relief Valve

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 speed at 1800-2100 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 pickup tube and screen assembly; refer to "26.11 Defective Pickup Screen Tube and Screen Assembly" .