Section 14.7 Faulty Thermostats

Section 14.7
Faulty Thermostats

To determine if faulty thermostats are causing high engine coolant temperature, perform the following:‪

  1. Remove thermostat from the thermostat housing, refer to MBE 900 Service Manual (6SE9007), cooling system chapter.
  2. Inspect thermostat for correct operation, refer to MBE 900 Service Manual (6SE9007), cooling system chapter.
    1. If thermostat is fully open at 95°C (203°F), check coolant pump; refer to "14.8 Faulty Coolant Pump" .
    2. If thermostat is not fully open at 95°C (203°F), refer to "14.7.1 Thermostat Replacement" .

Section 14.7.1
Thermostat Replacement

Perform the following steps to replace thermostats:‪

  1. Install new thermostat, refer to MBE 900 Service Manual (6SE9007), cooling system chapter.
  2. Verify replaced thermostat; refer to "14.7.1.1 Test Engine with New Thermostat" .
Section 14.7.1.1
Test Engine with New Thermostat

Perform the following steps to determine if thermostat replacement resolved high engine coolant temperature:‪

warning

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 70-95°C (158-203°F), no further troubleshooting is required. Shut down the engine.
    2. If the engine coolant temperature is not 70-95°C (158-203°F), shut down the engine. Check coolant pump; refer to "14.8 Faulty Coolant Pump" .


EPA07 MBE 900 DDEC VI Troubleshooting Guide - 6SE580
Generated on 10-13-2008

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