ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – 005-008   Engine Fuel Heater, Electric

The fuel heater is an optional device installed on the fuel filter head. It is held on the filter head by the threaded filter spud.

NOTE: The fuel heater is not controlled by the electronic control module (ECM). A bimetallic switch on the filter head acts as a thermostat. The fuel heater will turn on at approximately 1°C [34°F] and turn off at approximately 18°C [65°F].

The switch should register as an open circuit above 18°C [65°F] and register as a closed circuit below 1°C [34°F].

Remove the 2-pin connector from the fuel heater.

Check for proper voltage to the fuel heater.

NOTE: Minimum voltage is 12 VDC with keyswitch ON (separate 24 volt heaters are used on vehicles with a 24-volt charging system).

If the voltage is not within specifications, refer to the OEM troubleshooting and repair manual.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

WARNING  Fuel is flammable. Keep all cigarettes, flames, pilot lights, arcing equipment, and switches out of the work area and areas sharing ventilation to reduce the possibility of severe personal injury or death when working on the fuel system.

WARNING  Drain the fuel-water separator into a container, and dispose of contents in accordance with local environmental regulations.

• Disconnect the batteries. Refer to Procedure 013-009 in Section 13.
• Disconnect the OEM power supply connector from the fuel heater.
• Disconnect the engine harness connector from the water-in-fuel sensor.
• Drain a small quantity of fuel from the filter water drain to reduce fuel spillage during filter removal.
• Remove the spin-on fuel filter. Refer to Procedure 006-015 in Section 6.

Remove the threaded filter spud and fuel heater.

Install a new gasket onto the fuel heater.

Place the fuel heater, gasket side facing up, against the filter head with the electrical connector facing away from the engine block.

Apply thread-locker, Part Number 3375068, to the filter spud threads where they will engage the filter head.

Install the fuel filter spud.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Install the fuel filter. Refer to Procedure 006-015 in Section 6.
• Connect the fuel heater.
• Connect the water-in-fuel sensor.
• Connect the batteries. Refer to Procedure 013-009.