MBE 4000 DDEC VI Troubleshooting – Section 14.5 Incorrectly Adjusted Fan Belt

Section 14.5
Incorrectly Adjusted Fan Belt

To determine is a misadjusted fan belt is causing high engine coolant temperature, perform the following steps:‪

1. Check the auto tensioner for spring loading.
2. Compare tension to belt specifications.
   1. If the belt tension is normal, check the thermo-modulated fan; refer to "14.6 Inoperative Thermo-Modulated Fan" .
   2. If the belt tension is not normal, refer to "14.5.1 Belt Tension Resolution" .

Section 14.5.1
Belt Tension Resolution

Perform the following steps to resolve incorrect belt tension:‪

1. Replace the auto tensioner as required.
2. Verify belt tension resolution; refer to "14.5.1.1 Test Engine with Correct Belt Tension" .

Section 14.5.1.1
Test Engine with Correct Belt Tension

Perform the following to determine if belt tension resolved high engine coolant temperature:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

1. Start and run the engine.
2. Run the engine through its operating range with no-load for approximately five minutes, allowing the engine coolant to reach normal operating range.
   1. If the engine coolant temperature is 82-105°C (180-221°F), no further troubleshooting is required. Shut down the engine.
   2. If the engine coolant temperature is not 82-105°C (180-221°F), shut down the engine. Check thermo-modulated fan; refer to "14.6 Inoperative Thermo-Modulated Fan" .