Series 50 – Section 25.3 High Fuel Oil Temperature Return

Section 25.3
High Fuel Oil Temperature Return

To determine if high fuel oil temperature return is causing lack of power, perform the following:‪

1. Test for high fuel oil temperature return; refer to "24.4 High Fuel Oil Temperature Return" .
2. Analyze the high fuel oil temperature test results.
   1. If the return fuel oil temperature is less than or equal to 60°C (140°F), check for air cleaner restriction; refer to "25.4 Restricted Air Cleaner Element" .
   2. If the return fuel oil temperature is greater than 60°C (140°F), resolve the high fuel oil temperature return condition; refer to "25.3.1 High Fuel Oil Temperature Resolution" .

Section 25.3.1
High Fuel Oil Temperature Resolution

Perform the following steps to resolve high fuel oil temperature return:‪

1. Remove and replace fuel oil filter(s); refer to "2.7.1 Replacement of Fuel Filter" .
2. Inspect the check valve for a restricted fitting, replace if necessary; refer to "2.8.2 Fuel Return System Check Valve" .
3. Verify high fuel oil temperature repair; refer to "25.3.1.1 Test the Engine with Resolved High Fuel Oil Temperature" .

Section 25.3.1.1
Test the Engine with Resolved High Fuel Oil Temperature

Perform the following steps to determine if high fuel oil temperature repairs resolved lack of power condition: ‪

1. Start and run the engine.
2. Test drive the vehicle to ensure lack of power has been resolved.
   1. If no lack of power occurred during the test drive, no further troubleshooting is required. Shut the engine down.
   2. If lack of power occurred during the test drive, shut the engine down. Check for a restricted air cleaner element; refer to "25.4 Restricted Air Cleaner Element" .