Section 2.8
Defective Bypass Valve

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

1. Remove the oil filter adaptor; refer to appropriate service manual, lubrication system chapter.
2. Inspect the oil filter adaptor; refer to appropriate service manual, lubrication system chapter.
   1. If no damage is found with the oil filter adaptor components, reinstall the oil filter adaptor; refer to appropriate service manual, lubrication system chapter. Check pressure relief valve, refer to "2.9 Defective Pressure Relief Valve" .
   2. If damage is found with the oil filter adaptor components; refer to "2.8.1 Oil Filter Adaptor Repair" .

Section 2.8.1
Oil Filter Adaptor Repair

Perform the following steps to repair the oil filter adaptor:‪

1. Disassemble the oil filter adaptor; refer to appropriate service manual, lubrication system chapter.
2. Assemble the oil filter adaptor; refer to appropriate service manual, lubrication system chapter.

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

3. Install repaired oil filter adaptor; refer to appropriate service manual, lubrication system chapter.
4. Verify repairs made to the oil filter adaptor; refer to "2.8.1.1 Test Engine with Repaired Oil Filter Adaptor" .

Section 2.8.1.1
Test Engine with Repaired Oil Filter Adaptor

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

1. Connect to DDDL 7.0.
2. Start and vary the engine speed between 1800 -2100 rpm.
3. Visually examine DDDL 7.0 for oil pressure reading.
   1. If DDDL 7.0 indicates 241 kPa (35 psi) or more at 1800 rpm, shut down the engine and disconnect DDDL 7.0. No further troubleshooting is required.
   2. If DDDL 7.0 indicates less than 241 kPa (35 psi), shut down the engine and disconnect DDDL 7.0, check pressure relief valve; refer to "2.9 Defective Pressure Relief Valve" .