MBE 4000 DDEC VI Troubleshooting – Section 14.10 Abnormal Radiator Coolant Flow

Section 14.10
Abnormal Radiator Coolant Flow

To determine if abnormal radiator coolant flow is causing high engine coolant temperature, perform the following:‪

1. Install a sight glass with string (both ends) to the radiator outlet hose near radiator and before fill and heater return lines; see Figure "Radiator Flow Check" .
   

   Figure 1. Radiator Flow Check

   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.‪

2. Start and run the engine at full load.
3. Observe the string for flow and direction as well as the fill and bleed lines. Continue observation while varying the engine speed between 1800-2400 rpm.
   1. If a balanced coolant flow is observed in the sight glass, call Detroit Diesel Customer Support Center at 313-592-5800. Shut down the engine.
   2. If a balanced coolant flow is not observed in the sight glass, refer to "14.10.1 Abnormal Radiator Coolant Flow Resolution" . Shut down the engine.

Section 14.10.1
Abnormal Radiator Coolant Flow Resolution

Perform the following steps, as necessary, to resolve abnormal radiator coolant flow:‪

1. Correct bleed line size; refer to OEM guidelines.
2. Correct fill line size or connector fitting size; refer to OEM guidelines.
3. Correct restrictive top tank opening; refer to OEM guidelines.
4. Correct location of standpipe; refer to OEM guidelines.
5. Verify repairs made to correct abnormal radiator coolant flow; refer to "14.10.1.1 Test Engine with Resolved Radiator Coolant Flow" .

Section 14.10.1.1
Test Engine with Resolved Radiator Coolant Flow

Perform the following to determine if abnormal radiator coolant flow repair 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. Call the Detroit Diesel Customer Support Center at 313-592-5800.