Chevrolet Full Size Cars 1979-1989

Intake Manifold

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REMOVAL & INSTALLATION





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Fig. Fig. 1 Loosen the intake manifold retaining bolts



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Fig. Fig. 2 With the bolts removed, carefully lift the intake from the cylinder heads and block



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Fig. Fig. 3 Remove the old intake manifold gaskets



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Fig. Fig. 4 On some models, sealant should be applied to the intake-to-block mating surface

Inline 6-Cylinder Engine

The inline 6-cylinder engine covered by this guide is equipped an intake manifold which is integral with the cylinder head. For details on removal and installation, please refer to the cylinder head procedure found later in this section.

Chevrolet V and V8 Gasoline Engines


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Fig. Fig. 5 Common intake manifold installation Chevrolet gasoline engine



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Fig. Fig. 6 Intake manifold bolt torque sequence small block Chevrolet engine



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Fig. Fig. 7 Intake manifold bolt torque sequence 262 V6 engine

  1. Disconnect the negative battery cable, then remove the air cleaner assembly.
  2.  
  3. Drain the radiator to a level below the intake manifold.
  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:
  2.  
    1. Battery cables at the battery.
    2.  
    3. Upper radiator and heater hoses at the manifold.
    4.  
    5. Crankcase ventilation hoses as required.
    6.  
    7. Fuel line at the carburetor or the fuel line clips and lines at the throttle body, if equipped with fuel injection.
    8.  
    9. Accelerator linkage and TV cables.
    10.  
    11. Vacuum hose at the distributor (if equipped).
    12.  
    13. Power brake hose at the carburetor base or manifold, if applicable.
    14.  
    15. Ignition coil, the spark plug wires and temperature sending switch wires.
    16.  
    17. If equipped with CCC, disconnect the electrical harness and lay it aside.
    18.  

  3. Remove the distributor cap and scribe the rotor position relative to the distributor body.
  4.  
  5. Remove the distributor assembly from the engine.
  6.  
  7. If applicable, remove the alternator upper bracket. As required, remove the oil filler bracket, air cleaner bracket, air conditioning compressor and bracket, and accelerator bellcrank.
  8.  
  9. Remove the manifold-to-head attaching bolts, then remove the manifold and carburetor or throttle body as an assembly.
  10.  
  11. Using a putty knife clean the gasket and seal surfaces of the cylinder heads and manifold.
  12.  

To install:

  1. If the manifold is to be replaced, transfer the carburetor (and mounting studs) or throttle body, water outlet and thermostat (use a new gasket) heater hose adapter, EGR valve (use new gasket) and, if applicable, TVS switch and the choke coil. If equipped, use a new carburetor heat choke tube which must be transferred to a new manifold.
  2.  
  3. Install the new manifold end seals, folding the tabs (if applicable) and the manifold/head gaskets, using a sealing compound around the water passages.
  4.  
  5. Install the intake manifold assembly, taking care not to dislocate the end seals. It is helpful to use a pilot in the distributor opening. Tighten the manifold bolts to 30-35 ft. lbs. (41-47 Nm) in the proper torque sequence.
  6.  
  7. If applicable, install the alternator upper bracket. As required, install the oil filler bracket, air cleaner bracket, air conditioning compressor and bracket, and accelerator bellcrank.
  8.  
  9. Align the matchmarks made earlier and install the distributor to the engine making sure the rotor is facing the last of the matchmarks when the distributor housing is fully installed.
  10.  
  11. Connect all hoses, cables and wires which were disconnected for intake manifold removal.
  12.  
  13. Connect the negative battery cable, then properly refill the engine cooling system.
  14.  
  15. Start and run the engine, then check for leaks.
  16.  
  17. Check and adjust the timing, as necessary.
  18.  

Buick 231 V6 Gasoline Engine


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Fig. Fig. 8 Intake manifold torque sequence 231 V6 engine

A special wrench adapter, available from several tool manufacturers, is necessary to remove the left front intake manifold bolt.

  1. Disconnect the negative battery cable, then drain the engine cooling system.
  2.  

  1. Remove the upper radiator hose, and the coolant bypass hose from the manifold.
  2.  
  3. Remove the air cleaner assembly. Disconnect the throttle linkage from the carburetor. If necessary, remove the linkage bracket from the manifold, then disconnect the automatic transmission downshift linkage.
  4.  
  5. Disconnect the fuel line from the carburetor. If equipped with power brakes, disconnect the power brake line from the manifold. Disconnect the choke pipe and all vacuum lines. Disconnect the anti-dieseling solenoid wire.
  6.  
  7. Remove the manifold bolts. It will be necessary to remove the distributor cap and rotor to gain access to the front left manifold bolt. This is a special fastener known as a Torx® bolt. Tag and disconnect the plug wires from the plugs.
  8.  
  9. Remove the manifold.
  10.  
  11. Thoroughly clean the gasket mating surfaces on the engine and the intake manifold.
  12.  

To install:

  1. Position new gaskets and seals on the engine. Coat the ends of the seals with a non-hardening silicone sealer. The pointed end of the seal should be a snug fit against the block and head.
  2.  
  3. When installing the manifold, start with the center bolts (numbers one and two) and slowly tighten them until snug. Continue with the rest of the bolts in sequence, tightening them in several stages to the correct torque.
  4.  
  5. Connect the anti-dieseling solenoid wire, the choke pipe and all vacuum lines.
  6.  
  7. If equipped with power brakes, connect the line to the manifold.
  8.  
  9. Connect the fuel line to the carburetor, then if removed, secure the linkage bracket to the manifold.
  10.  
  11. If equipped with an automatic transmission, connect the downshift linkage to the carburetor.
  12.  
  13. Connect the throttle linkage to the carburetor.
  14.  
  15. Install the air cleaner assembly, then connect the upper radiator hose and coolant bypass hose to the intake.
  16.  
  17. Connect the negative battery cable, then properly refill the engine cooling system.
  18.  
  19. Start and run the engine, then check for leaks.
  20.  

307 Oldsmobile Engine


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Fig. Fig. 9 Intake manifold mounting Oldsmobile produced 307 V8 engine



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Fig. Fig. 10 Intake manifold torque sequence Oldsmobile V8 engine

  1. Disconnect the negative battery cable, then drain the cooling system.
  2.  

  1. Remove the air cleaner assembly, then if necessary, remove the carburetor assembly from the intake manifold.
  2.  
  3. If equipped with cruise control remove the servo assembly.
  4.  
  5. Remove the top radiator hose, then disconnect the fuel line and remove it for accessibility. As necessary, remove the alternator and/or the air conditioning compressor mounting bolts.
  6.  
  7. Tag and disconnect all required electrical wires, vacuum lines and throttle cables.
  8.  
  9. Loosen and remove the intake manifold retaining bolts, then carefully lift the intake manifold from the engine.
  10.  

To install:

  1. Coat both sides of the gasket surface that seal the intake manifold to the cylinder heads with G.M. sealer #1050026 or equivalent, then position the gaskets on the cylinder heads.
  2.  
  3. Use an RTV sealer on the end seals, then place the end seals on the block, making sure that the ends are positioned under the cylinder heads.
  4.  
  5. Install the manifold to the engine. Dip the bolts in clean engine oil, then install and tighten them to 40 ft. lbs. (54 Nm).
  6.  
  7. As necessary, install and secure the alternator and/or compressor mounting bolts.
  8.  
  9. If removed, install the carburetor. Engage all required electrical connections, vacuum lines and throttle linkages, as noted during removal.
  10.  
  11. Install the fuel line, then connect the top radiator hose.
  12.  
  13. Install the air cleaner assembly, then connect the negative battery cable.
  14.  
  15. Properly refill the engine cooling system, then start the engine and check for leaks.
  16.  

Diesel Engine


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Fig. Fig. 11 Exploded view of a diesel intake manifold and gaskets



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Fig. Fig. 12 V8 diesel intake manifold bolt torque sequence

  1. Disconnect the negative battery cable, then remove the air cleaner assembly.
  2.  
  3. Drain the radiator and loosen the upper bypass hose clamp. Remove the thermostat housing bolts, the housing and the thermostat from the intake manifold.
  4.  

  1. Remove the breather pipes from the rocker covers and the air crossover. Remove the air crossover.
  2.  
  3. Disconnect the throttle rod and the return spring. If equipped with cruise control, remove the servo.
  4.  
  5. Remove the hairpin clip at the bellcrank and disconnect the cables. Remove the throttle cable from the bracket on the manifold; position the cable away from the engine. Disconnect and label any wiring as necessary.
  6.  
  7. If necessary, remove the alternator bracket. If equipped with air conditioning, remove the compressor mounting bolts and move the compressor aside, without disconnecting any of the hoses. Remove the compressor mounting bracket from the intake manifold.
  8.  
  9. Disconnect the fuel line from the pump and the fuel filter. Remove the fuel filter and bracket.
  10.  
  11. Remove the fuel injection pump and lines. Please refer to of this guide for details and procedures.
  12.  
  13. Disconnect and remove the vacuum pump or oil pump drive assembly from the rear of the engine.
  14.  
  15. Remove the intake manifold drain tube.
  16.  
  17. Remove the intake manifold bolts and the manifold. Remove the adapter seal and the injection pump adapter.
  18.  
  19. Clean the mating surfaces of the cylinder heads and the intake manifold using a putting knife.
  20.  

To install:

  1. Coat both sides of the gasket surface that seal the intake manifold to the cylinder heads with G.M. sealer #1050026 or the equivalent.
  2.  
  3. Position the intake manifold gaskets on the cylinder heads. Install the end seals, making sure that the ends are positioned under the cylinder heads.
  4.  
  5. Carefully lower the intake manifold into place on the engine.
  6.  
  7. Clean the intake manifold bolts thoroughly, then dip them in clean engine oil. Install the bolts and tighten to 15 ft. lbs. (20 Nm) in the sequence shown. In a second pass of the sequence, tighten all the bolts to 30 ft. lbs. (41 Nm). Finally, in a third pass of the sequence, tighten the bolts to 40 ft. lbs. (54 Nm).
  8.  
  9. Install the intake manifold drain tube and clamp. Apply a coating of RTV sealer to the cone shaped surface of the drain tube and on the chamfered hole of the intake manifold. Also, apply a coating of sealer to the threads of the clamp bolt.
  10.  
  11. Install injection pump adapter. Refer to of this guide for details. If a new adapter is not being used, be sure to skip the steps for preparing a new adapter, as noted.
  12.  
  13. Install and connect the vacuum pump or oil pump drive assembly from the rear of the engine.
  14.  
  15. Install the fuel injection pump and lines.
  16.  
  17. Install the fuel filter and bracket, then connect the fuel line to the pump and filter.
  18.  
  19. If equipped with A/C, install the compressor bracket to the intake manifold, then reposition and secure the compressor assembly.
  20.  
  21. If removed, install the alternator bracket.
  22.  
  23. Connect the wiring as tagged during removal.
  24.  
  25. Connect the throttle cable and secure it in the bracket. Connect the cables and install the hairpin clip at the bellcrank.
  26.  
  27. If equipped with cruise control, install the servo.
  28.  
  29. Connect the throttle rod and return spring.
  30.  
  31. Install the air crossover, then connect the breather pipes to the rocker covers and the crossover.
  32.  
  33. Install the thermostat housing and tighten the retaining bolts, then connect and tighten the upper bypass hose clamp.
  34.  
  35. Connect the negative battery cable and properly refill the engine cooling system.
  36.  
  37. Start and run the engine, then check for leaks.
  38.  

 
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