Nissan Pick-ups and Pathfinder 1970-1988

Intake Manifold

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REMOVAL & INSTALLATION



L16, L18 and L20B Engines

See Figure 1

  1. Remove the air cleaner assembly together with all of the attending hoses. Remove the EGR tube on 1974-80 models.
  2.  
  3. Drain the cooling system and disconnect the battery.
  4.  

It is important to replace the gasket whenever the intake manifold is removed. Because the intake and exhaust manifolds share a common gasket, whenever the intake manifold is removed, the exhaust manifold must also be removed, so that the gasket can be replaced.

  1. Disconnect the throttle linkage, fuel, and vacuum lines from the carburetor. Label all wires and hoses as they are removed to simplify installation.
  2.  
  3. The carburetor can be removed from the manifold at this point or can be removed as an assembly with the intake manifold.
  4.  
  5. Loosen the intake manifold attaching nuts, working from the two ends toward the center, and then remove them.
  6.  
  7. Remove the intake manifold from the engine.
  8.  

To install:
  1. Cover the cylinder head ports with shop cloths to keep anything from falling into the cylinder head or block.
  2.  
  3. When installing the intake manifold, always use a new gasket. Tighten the manifold bolts from the center outwards, in two progressive steps, to 9-12 ft. lbs. (12-16 Nm).
  4.  
  5. Install the carburetor (if removed), then connect all hoses and lines. Install the air cleaner and fill the cooling system.
  6.  



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Fig. Fig. 1: Intake manifold-L16, L18 and L20B engines

Z20, Z22, Z24 and Z24i Engines

See Figures 2, 3, 4, 5, 6 and 7

Always release the fuel pressure on fuel injected engines before removing any fuel system component.

  1. Drain the coolant and disconnect the battery cable.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. On the Z24i, remove the air cleaner hoses. On the Z20, Z22 and Z24, remove the air cleaner.
  2.  
  3. Remove the radiator hoses from the manifold.
  4.  
  5. On the Z20, Z22 and Z24, remove the fuel, air and vacuum hoses from the carburetor. Remove the throttle linkage and remove the carburetor.
  6.  
  7. Remove the throttle cable and disconnect the fuel pipe and the return fuel line on the Z24i. Plug the fuel pipe to prevent spilling fuel.
  8.  

When unplugging wires and hoses, mark each hose and its connection with a piece of masking tape, then mark the two pieces of tape with the numbers 1, 2, 3, etc. When assembling, simply match the pieces of tape.

  1. Remove all remaining wires, tubes, the air cleaner bracket (Z20, Z22 and Z24) and the EGR and PCV tubes from the rear of the intake manifold. Remove the air induction pipe from the front of the engine (Z20, Z22 and Z24). Remove the manifold supports on the Z24i.
  2.  
  3. Unbolt and remove the intake manifold. On the Z24i, remove the manifold with injectors, EGR valve, fuel tubes, etc., still attached.
  4.  

To install:
  1. Clean the gasket mounting surfaces then install the intake manifold on the engine. Always use a new intake manifold gasket. Tighten the mounting bolts from the center, out, to 12-15 ft. lbs. (16-21 Nm)
  2.  
  3. Connect all electrical connections, tubes, the air cleaner bracket (Z20, Z22 and Z24) and the EGR and PCV tubes to the rear of the intake manifold. Install the air induction pipe to the front of the engine (Z20, Z22 and Z24). Install the manifold supports on the Z24i.
  4.  
  5. Install the throttle cable and reconnect the fuel pipe and the return fuel line on the Z24i.
  6.  
  7. Install the carburetor and throttle linkage. Reconnect the fuel, air and vacuum hoses to the carburetor on these models.
  8.  
  9. Install the radiator hoses to the intake manifold.
  10.  
  11. On the Z24i, install the air cleaner hoses. On all other engines, install the air cleaner.
  12.  
  13. Refill the coolant level and connect the battery cable. Start the engine and check for leaks.
  14.  



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Fig. Fig. 2: Intake manifold-Z20, Z22 and Z24 engines



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Fig. Fig. 3: Intake manifold-Z24i engines



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Fig. Fig. 4: Removing the intake manifold bolts



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Fig. Fig. 5: Removing the fuel line for intake manifold removal



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Fig. Fig. 6: Removing the intake manifold



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Fig. Fig. 7: View of the intake manifold-to-engine mounting

VG30i Engines

See Figures 8, 9 and 10

  1. Release the fuel system pressure ( General Information & Maintenance ) and disconnect the battery cables.
  2.  
  3. Drain coolant by removing the drain plug on the left side of the cylinder block.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect all valves, lines, hoses, cables and or brackets to gain access to the collector cover and collector assembly retaining bolts.
  2.  
  3. Remove the collector cover. Remove the collector-to-intake manifold bolts in numerical order.
  4.  
  5. Remove the intake manifold and injection unit assembly. Loosen intake manifold bolts in the sequence shown.
  6.  

To install:
  1. Install the intake manifold and injection unit assembly with a new gasket to the engine. Tighten the manifold bolts and nuts in two or three stages, to 12-14 ft. lbs. (16-20 Nm) in the order shown.
  2.  
  3. Install the collector and collector cover with new gaskets. Tighten collector-to-intake manifold bolts in two or three stages, in the reverse order of removal.
  4.  
  5. Connect all valves, lines, hoses, cables and or brackets to the collector cover and collector assembly.
  6.  
  7. Refill the cooling system. Reconnect the battery cables.
  8.  
  9. Check fluid levels, start the engine and check for leaks.
  10.  



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Fig. Fig. 8: Intake manifold assembly-VG30i engine



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Fig. Fig. 9: Intake manifold bolt loosening sequence-VG30i engine



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Fig. Fig. 10: Intake manifold bolt tightening sequence-VG30i engine

SD22 and SD25 Engines

See Figure 11

  1. Drain the coolant and disconnect the battery cable.
  2.  
  3. Tag and disconnect the lines and hoses at the throttle chamber/venturi, dropping resistor and breather. On California SD22 engines, disconnect the EGR pipe at the valve.
  4.  
  5. Disconnect and remove the dashpot from the intake manifold on SD22 engines (exhaust manifold-Calif.).
  6.  
  7. Remove the intake manifold.
  8.  

To install:
  1. Scrape any old gasket material off the cylinder head mounting surface and install the manifold using a new gasket. Tighten the bolts gradually, in two or three stages.
  2.  
  3. Install the dashpot and connect all lines, hoses and pipes.
  4.  
  5. Refill the cooling system.
  6.  



Click image to see an enlarged view

Fig. Fig. 11: Intake and exhaust manifolds-Calif. SD22 engine shown (others diesel similar)

 
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