How to Restart a Detroit Diesel After Changing Fuel Filters

by Grace Mclain
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The Detroit Diesel series engines come equipped with primary and secondary fuel filters. Both filters cleanse the fuel before it reaches the fuel injectors. The diesel is pumped out of the tank and into the fuel lines, and then flows into the fuel filters. Any sediment from the diesel will get trapped inside of each fuel filter, allowing the cleansed fuel to flow to the injectors and engine. The fuel system will require priming after the fuel filters are replaced.

Step 1

Locate the primer bulb on top of the primary fuel filter housing, located on the right-hand side of the engine. Press the primer bulb in and out with your hand and a clean rag until the bulb will no longer push in. This means the fuel filters are full of diesel.

Step 2

Move to the driver's seat and turn the ignition to the accessory position for about 10 seconds. This will heat the glow plugs and finish priming the fuel filters.

Step 3

Crank the engine. Let it run for about 15 seconds to completely remove any air from the fuel system. Inspect the fuel filters for any leaks.

Turn the engine off for about 10 seconds, then restart it to make sure all of the air is out of the fuel system. Turn the engine back off.


  • Both new fuel filters must be filled completely full of fresh diesel before installing them to the fuel filter housing.
  • If the secondary fuel filter is a bowl fuel filter, use pliers to remove the top plug, then fill the fuel filter up with diesel.


  • If the new fuel filters are not completely filled with fresh diesel, the engine will not crank because air will get into the fuel system and cause vapor lock.
  • Never smoke or use open flames around gas.
  • Refer to local and state laws when disposing of used fuel and used fuel filters.

Items you will need

  • Clean rags

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