GM Full Size Vans 1967-1986 Repair Guide

Fuel Filter

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REMOVAL & INSTALLATION



Gasoline Engines

See Figure 1



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Fig. Fig. 1: The paper fuel filter element can be found in the inlet fitting

The fuel filter should be serviced at the interval given on the Maintenance Interval chart. Two types of fuel filters are used, a bronze type and a paper element type. Inline fuel filters may be used on some engines which should be changed at the same time as the filter in the carburetor body. Filter replacement should be attempted only when the engine is cold. Additionally, it is a good idea to place some absorbent rags under the fuel fittings to catch the gasoline which will spill out when the lines are loosened. To replace the filter found in the carburetor body:

  1. Disconnect the fuel line connecting at the intake fuel filter nut. Plug the opening to prevent loss of fuel.
  2.  
  3. Remove the intake fuel filter nut from the carburetor with a 1 in. (25mm) wrench.
  4.  
  5. Remove the filter element and spring.
  6.  
  7. Check the element for restrictions by blowing on the cone end. Air should pass freely.
  8.  
  9. Clean or replace the element, as necessary.
  10.  
  11. Install the element spring, then the filter element in the carburetor. Bronze filters should have the small section of the cone facing out.
  12.  
  13. Install a new gasket on the intake fuel nut. Install the nut in the carburetor body and tighten securely.
  14.  
  15. Install the fuel line and tighten the connector.
  16.  

Some trucks may have an inline filter. This is a can shaped device located in the fuel line between the pump and the carburetor. It may be made of either plastic or metal. To replace the filter:

  1. Place some absorbent rags under the filter. Remember, it will be full of gasoline when removed.
  2.  
  3. Use a pair of pliers to expand the clamp on one end of the filter, then slide the clamp down past the point to which the filter pipe extends in the rubber hose. Do the same with the other clamp.
  4.  
  5. Gently twist and pull the hoses free of the filter pipes. Remove and discard the old filter.
  6.  

Most replacement filters come with new hoses that should be installed with a new filter.

  1. Install the new filter into the hoses, slide the clamps back into place, and check for leaks with the engine idling.
  2.  

6.2L Diesel Engines

The 1983 diesels utilize two fuel filters: a primary canister type screw-on filter, located on the chassis right hand under body cross sill forward of the fuel tank, and a clip-on secondary filter mounted on the rear of the intake manifold. The 1984-86 models use a combination fuel filter and water separator. These filters should be serviced at the regular intervals specified in the Maintenance chart. See Diesel Fuel System in Fuel System for more information.

1983 MODELS

See Figures 2 and 3

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Fig. Fig. 2: Exploded view of the primary fuel filter-1983 6.2L diesel engines



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Fig. Fig. 3: Exploded view of the secondary fuel filter-1983 6.2L diesel engines

  1. Remove the engine cover.
  2.  
  3. Remove the air cleaner and place a rag under the filter.
  4.  
  5. Unstrap the lower bail on the filter to relieve fuel pressure in the filter.
  6.  
  7. Unstrap the upper bail and remove the filter.
  8.  
  9. Before installing the new filter, insure that both filter mounting plate fittings are clear of dirt.
  10.  
  11. Install the new filter, snap the upper bail clamp only. Any time the secondary filter is removed or replaced, the air must be purged from the filter to prevent the engine from stalling or excessive cranking time to restart.
  12.  
  13. Disconnect the pink electrical wire from the injection pump to prevent the engine from starting.
  14.  
  15. Crank the engine (for 10 seconds max.) until the fuel is flowing at the lower fitting.
  16.  
  17. If the fuel is not observed for 10 seconds, wait 15 seconds and repeat Step 8.
  18.  
  19. When fuel is observed at the lower fitting, connect the lower bail clamp.
  20.  
  21. Reconnect the pink wire on the injection pump and install the air cleaner.
  22.  
  23. Start the engine and allow it to idle for several minutes to purge the remaining air. Check for fuel leaks.
  24.  
  25. Remove the rag and reinstall the engine cover.
  26.  

1984-86 MODELS

See Figure 4

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Fig. Fig. 4: View of the combination fuel filter/water separator-1984 6.2L diesel engines

  1. Drain the fuel from the fuel filter by opening both the air bleed and the water drain valve allowing the fuel to drain out into an appropriate container.
  2.  
  3. Remove the fuel tank cap to release any pressure or vacuum in the tank.
  4.  
  5. Unstrap both bail wires with a screwdriver and remove the filter.
  6.  
  7. Before installing the new filter, insure that both filter mounting plate fittings are clear of dirt.
  8.  
  9. Install the new filter, snap into place with the bail wires.
  10.  
  11. Close the water drain valve and open the air bleed valve. Connect a 1 / 8 in. (3mm) I.D. hose to the air bleed port and place the other end into a suitable container.
  12.  
  13. Disconnect the fuel injection pump shut off solenoid wire.
  14.  
  15. Crank the engine for 10-15 seconds, then wait one minute for the starter motor to cool. Repeat until clear fuel is observed coming from the air bleed.
  16.  

If the engine is to be cranked, or starting attempted with the air cleaner removed, care must be taken to prevent dirt from being pulled into the air inlet manifold which could result in engine damage.

  1. Close the air bleed valve, reconnect the injection pump solenoid wire and replace the fuel tank cap.
  2.  
  3. Start the engine, allow it to idle for 5 minutes and check the fuel filter for leaks.
  4.  

 
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