Series 50 – Section 26.9 Defective Bypass Valve

Section 26.9
Defective Bypass Valve

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

1. Remove the oil filter adaptor; refer to "3.6.2 Cleaning and Removal of Oil Filter Adaptor" .
2. Inspect the oil filter adaptor; refer to "3.6.2.1 Inspection of Oil Filter Adaptor" .
   1. If no damage is found with the oil filter adaptor components. Reinstall the oil filter adaptor; refer to "3.6.4 Installation of Oil Filter Adaptor" , check pressure relief valve; refer to "26.10 Defective Pressure Relief Valve" .
   2. If damage is found with the oil filter adaptor components; refer to "26.9.1 Oil Filter Adaptor Repair" .

Section 26.9.1
Oil Filter Adaptor Repair

Perform the following steps to repair the oil filter adaptor:‪

1. Disassemble the oil filter adaptor; refer to "3.6.2 Cleaning and Removal of Oil Filter Adaptor" .
2. Inspect oil filter adaptor, refer to "3.6.2.1 Inspection of Oil Filter Adaptor" .
3. Assemble the oil filter adaptor; refer to "3.6.3 Assembly of Oil Filter Adaptor" .

   Note: Always replace the copper washer whenever the adaptor plug is removed.

4. Install repaired oil filter adaptor; refer to "3.6.4 Installation of Oil Filter Adaptor" .
5. Verify repairs made to the oil filter adaptor; refer to "26.9.1.1 Test Engine with Repaired Oil Filter Adaptor" .

Section 26.9.1.1
Test Engine with Repaired Oil Filter Adaptor

Perform the following to determine if repaired oil pressure regulator 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 vary the engine speed between 1800 -2100 r/min.
3. Visually examine the DDR for oil pressure reading.
   1. If the DDR indicates 241 kPa (35 lb/in.² ), 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 ), shut down the engine and disconnect the DDR, check pressure relief valve; refer to "26.10 Defective Pressure Relief Valve" .