Nissan Pick-ups and Pathfinder 1970-1988

Fuel Filter

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REMOVAL & INSTALLATION




CAUTION
NEVER SMOKE WHEN WORKING AROUND OR NEAR GASOLINE! MAKE SURE THAT THERE IS NO ACTIVE IGNITION SOURCE NEAR YOUR WORK AREA!

1970-83 Carbureted Engines

See Figures 1 and 2

The fuel filter is located on the right inner fender in the engine compartment. It is a disposable cartridge type.

  1. Using a pair of pliers, expand the hose clamp on one side of the filter, and slide the clamp further down the hose, past the point to which the filter pipe extends. Remove the other clamp in the same manner.
  2.  
  3. Grasp the hoses near the ends and twist them gently to pull them free from the filter pipes.
  4.  
  5. Pull the filter from the clip and discard.
  6.  
  7. Install the new filter into the clip. Push the hoses onto the filter pipes, and slide the clamps back into position. Start the engine and check for leaks.
  8.  



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Fig. Fig. 1: Fuel filter-1970-79



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Fig. Fig. 2: Fuel filter-1980-83

1984-86 Carbureted Engines

See Figures 3, 4, 5 and 6

The fuel filter is located on the inside of the frame above the left rear spring front shackle.

Changing the filter is VERY awkward. Since it is in-line and below tank level, fuel will pour from the fuel lines when they are disconnected from the filter. The only way of preventing this, is to siphon all of the gasoline from the tank before replacing the filter. Another possible method is to clamp and plug the fuel line, but this is not recommended because of the danger of leaking fuel or damage which could occur to the fuel line when clamped. It would, therefore, be a good idea to run the tank almost dry before changing the filter. Once the tank is dry, disconnect the fuel lines at the filter, unbolt the old filter and install a new one. Reconnect the fuel lines, fill the tank, start the engine and check for leaks.



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Fig. Fig. 3: Fuel filter-1984-86



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Fig. Fig. 4: Remove the shield mounting bolts



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Fig. Fig. 5: Remove the shield, if necessary for fuel filter removal



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Fig. Fig. 6: Removing fuel filter-always replace fuel line clamps

Fuel Injected Engines

WARNING
Never attempt to remove the fuel filter without first relieving the fuel system pressure!

See Figures 7 and 8

  1. Release the fuel pressure from the fuel line as follows:
    1. Remove the fuel pump fuse at the fuse box.
    2.  
    3. Start the engine.
    4.  
    5. After the engine stalls, crank the engine two or three times to make sure that the fuel pressure is released.
    6.  
    7. Turn the ignition switch OFF and reinstall the fuel pump fuse.
    8.  

  2.  
  3. Loosen the hose clamps at the fuel inlet and outlet lines then slide each line off the filter nipples.
  4.  
  5. Remove the fuel filter.
  6.  
  7. Replace the fuel filter. Always be sure to use new hose clamps.
  8.  



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Fig. Fig. 7: Fuel filter-1986-88 VG30i



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Fig. Fig. 8: Fuel filter-1986-88 Z24i

Diesel Engines

See Figures 9 through 13

Two filters are used in the fuel system on 1981-86 720 Series models; a large spin-on type and a smaller in-line type. The larger filter, called the main filter, is located on the right front fender inner liner. The smaller filter, called the primary filter, is located on the firewall, in the engine compartment.

On 1986-87 D20 Series models there is one filter and a sedimentor/fuel heater. Both units can be found in the back right corner of the engine compartment, in a bracket attached to the firewall.

1981-86 720 SERIES MAIN FILTER
  1. Disconnect the fuel filter sensor connector (if equipped) at the lower end of the filter.
  2.  
  3. Drain the fuel from the filter, loosen the two mounting bolts and remove the filter.
  4.  
  5. Unscrew the filter from the housing. An oil filter strap wrench may come in handy when removing the filter.
  6.  

To install:
  1. Coat the filter gasket lightly with diesel fuel and then screw it in hand-tight. Next, use the strap wrench and turn the filter 3 / 4 turn more.
  2.  
  3. Mount the filter assembly, tighten the bolts and connect the sensor switch.
  4.  
  5. Bleed the fuel system.
  6.  
  7. Using the priming pump on the injection pump, fill the filter with fuel and check for leaks.
  8.  

1981-86 720 SERIES PRIMARY FILTER
  1. Using a pair of pliers, expand the hose clamp on one side of the filter, and slide the clamp further down the hose, past the point to which the filter pipe extends. Remove the other clamp in the same manner.
  2.  
  3. Grasp the hoses near the ends and twist them gently to pull them free from the filter pipes.
  4.  
  5. Pull the filter from the clip and discard.
  6.  
  7. Install the new filter into the clip. Push the hoses onto the filter pipes, and slide the clamps back into position. Start the engine and check for leaks.
  8.  

On the SD25, be sure to install the primary fuel filter with the word UPPER facing upward!

1986-87 D21 SERIES
  1. Position a rag underneath the filter and remove the fuel line.
  2.  
  3. Drain the fuel from the filter as detailed in Fuel System .
  4.  
  5. Unscrew the fuel filter from the bracket head. It should come off with your hands. If not, use an oil filter strap wrench to help it along, but be careful!
  6.  

To install:
  1. Clean the fuel filter mounting surface on the bracket. Coat the rubber gasket on a new filter with diesel fuel and then screw it into the bracket until it is snug. Tighten it an additional 2 / 3 turn. Do not use a strap wrench for installation!
  2.  
  3. Bleed the fuel system, start the engine and check for any leaks.
  4.  



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Fig. Fig. 9: Fuel filter (main)-1981-86 SD22 and SD25 engines (720-D series)



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Fig. Fig. 10: Fuel filter (primary)-1981-83 SD22 engine



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Fig. Fig. 11: Fuel filter (primary)-1984-86 SD25 engine (720-D series)



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Fig. Fig. 12: When installing the primary filter on 1984-86 SD25 engine (720-D series) be sure that the word UPPER faces upward



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Fig. Fig. 13: Fuel filter and sedimentor-1986-87 SD25 engine (D21-D series)

DRAINING WATER FROM THE DIESEL FUEL FILTER

WARNING
When the fuel filter warning light or buzzer comes on, the water in the fuel filter must be drained immediately.

See Figures 14 and 15

  1. Raise the hood and position a small pan or jar underneath the main filter to catch the water about to be released.
  2.  
  3. Reach under the fuel filter and, on 1981-83 models, remove the fuel filter sensor connector. On 1984-87 models, simply loosen the drain valve under the filter 4 or 5 times until the water begins to come out. DO NOT remove the drain valve/connector on 1984-87 models.
  4.  
  5. Depressing the priming pump will usually speed the removal of water from the filter. The pump can be found on the side of the injection pump housing on 1981-86 models (720 series) and on top of the filter mounting bracket on 1986-87 models (D21 series). Pump the priming pump until fuel is the only substance being forced out.
  6.  

BLEEDING THE FUEL SYSTEM

Air should be bled from the fuel system on diesel engines whenever the system has been opened.

  1. Locate the priming pump. On 1981-86 models (720 series), its on the side of the injection pump (remove the cap); on 1986-87 models (D21 series), its on top of the filter mounting bracket.
  2.  
  3. Rotate the priming pump counterclockwise (720 series only) and then loosen the air vent screw on the side of the injection pump housing (720 series) or on the side of the filter mounting bracket (D21 series).
  4.  

SD22 engines utilize two (2) air vent screws.

  1. Pump the priming pump until all air has been expelled through the vent hole and then tighten the air vent screw.
  2.  
  3. On 720 series models, press the priming pump down and turn it clockwise. Install the pump cap.
  4.  



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Fig. Fig. 14: Priming pump (2) and air vent screw (1)-1981-86 SD22 and SD25 engines (720-D series)



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Fig. Fig. 15: Priming pump and air vent screw-1986-87 SD25 engine (D21-D series)

 
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