GM Cutlass RWD 1970-1987 Repair Guide

Intake Manifold

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REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4 and 5

L-6 Engine

1975 and later L-6 engines are equipped with an intake manifold which is integral with the cylinder head and cannot be removed. Earlier inline 6 engines use a combined intake/exhaust manifold. Both are removed together.

  1. Remove the air cleaner assembly.
  2.  
  3. Disconnect the throttle linkage at the carburetor. Detach and tag the fuel lines and vacuum lines from the carburetor.
  4.  
  5. Remove the PCV valve and hose from the valve cover. Disconnect the air supply hose from the check valve on the air injection manifold, if so equipped.
  6.  
  7. Unbolt the exhaust manifold from the exhaust pipe. Spray the threads with a rust penetrant first.
  8.  
  9. Unbolt the manifold bolts and clamps.
  10.  
  11. Remove the manifold assembly. If you wish to separate the manifold, unfasten the single bolt and two nuts at the center of the assembly.
  12.  

To install:
  1. Use new gaskets and make sure the ports are free of any debris.
  2.  
  3. Install the manifold and fasten the manifold bolts and clamps
  4.  
  5. Install the exhaust manifold.
  6.  
  7. Install the air supply hose and the PCV valve.
  8.  
  9. Reconnect the fuel lines and throttle linkage
  10.  
  11. Install the air cleaner
  12.  

Buick Built Engines
  1. Disconnect the negative battery cable and drain the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by 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. Remove the air cleaner.
  2.  
  3. Disconnect the upper radiator hose and the heater hose at the manifold.
  4.  
  5. Disconnect the accelerator linkage at the carburetor and the linkage bracket at the manifold. Remove the cruise control chain, if so equipped.
  6.  
  7. Remove the fuel line from the carburetor and the booster vacuum pipe from the manifold.
  8.  
  9. On 1976 models, disconnect the choke pipe at the choke housing.
  10.  
  11. Disconnect and label the transmission vacuum modulator line, idle stop solenoid wire (if so equipped), distributor wires and the temperature sending unit wire.
  12.  
  13. Disconnect and tag the vacuum hoses at the distributor and the carburetor.
  14.  
  15. Disconnect the coolant bypass hose at the manifold.
  16.  
  17. On six cylinder models, remove the distributor cap and wires to gain access to the Torx head bolt. Remove the bolt.
  18.  



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Fig. Fig. 1: Intake manifold torque sequence - Buick built engines



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Fig. Fig. 2: TORX® head bolt

  1. Remove the throttle linkage springs. On 1976 models, remove and tag the spark plug wires.
  2.  
  3. Remove the A/C compressor top bracket, if so equipped.
  4.  
  5. Remove the manifold.
  6.  

To install:
  1. Use a new gasket to install. Use sealer on the end of the rubber gasket seals. Carefully guide the manifold onto the engine block dowel pin. Tighten the bolts in the proper order.
  2.  
  3. Install the throttle linkage springs.
  4.  
  5. On 6 cylinder models, reinstall the wires and distributor
  6.  
  7. Install the coolant bypass hose and the vacuum hoses.
  8.  
  9. Install the temperature sending unit, idle stop solenoid wire (if so equipped), and connect the vacuum modulator line
  10.  
  11. On 1976 models, connect the choke pipe
  12.  
  13. Install the booster vacuum pipe and the fuel line
  14.  
  15. Install the cruise control chain (If so equipped), linkage bracket at the manifold and the accelerator linkage
  16.  
  17. Install the heater hose and the upper radiator hose.
  18.  
  19. Install the air cleaner, fill the radiator with coolant and connect the negative battery cable.
  20.  

V8 Chevrolet Built Engines.

  1. Drain the cooling system.
  2.  
  3. Remove the air cleaner.
  4.  
  5. Disconnect the battery ground.
  6.  
  7. Disconnect the upper radiator hose and the heater hose at the manifold.
  8.  
  9. Disconnect and tag all linkage and hoses attached to the manifold and/or carburetor.
  10.  
  11. Remove the distributor, mark the rotor position with chalk on the distributor body, then remove the distributor.
  12.  
  13. Remove the air cleaner bracket, air pump and bracket, accelerator return spring and bracket and accelerator bell crank.
  14.  



Click image to see an enlarged view

Fig. Fig. 3: Intake manifold sequence - 267, 305, and 350 Chevrolet built engines



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Fig. Fig. 4: Intake manifold torque sequences - 263 diesel engine



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Fig. Fig. 5: Intake manifold torque sequence, 260, 307, 350, 403 Oldsmobile built gasoline and diesel engines

  1. Remove the alternator upper mounting bracket.
  2.  
  3. Unbolt and remove the manifold.
  4.  

To install:
  1. Install the manifold and the alternator upper mounting bracket.
  2.  
  3. Install the accelerator bellcrank and the return spring.
  4.  
  5. Install the air pump and bracket, and connect the air cleaner bracket.
  6.  
  7. Install the distributor and connect all linkage and hoses to the manifold and/or carburetor
  8.  
  9. Connect the radiator hose, air cleaner and negative battery cable
  10.  

V8 Oldsmobile Built Gasoline Engines
  1. Remove the air cleaner, drain the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by 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 the upper radiator hose, bypass hose, and heater hose from the manifold.
  2.  
  3. Disconnect the throttle linkage, vacuum and gas lines from the carburetor.
  4.  
  5. Remove the alternator and air conditioning compressor brackets if necessary.
  6.  


CAUTION
Do not disconnect the A/C lines. Personal injury could result.

  1. Disconnect the temperature gauge wire. Remove the oil filler tube on 455 engines.
  2.  
  3. Remove the intake manifold bolts and remove the manifold with the carburetor attached.
  4.  

To install:
  1. Install the manifold, tightening the bolts first to 15 ft. lbs. (20 Nm), then to the figure specified in the torque chart, in the sequence illustrated. Coat all gasket surfaces with sealer.
  2.  
  3. On 455 engines install the oil filler tube
  4.  
  5. Connect the temperature gauge wire and the air conditioning compressor brackets (if necessary)
  6.  
  7. Connect the fuel lines, vacuum lines and the throttle linkage.
  8.  
  9. Connect the heater hose, by-pass hose and the upper radiator hose.
  10.  
  11. Install the air cleaner and fill the radiator with coolant.
  12.  

263 and 350 Oldsmobile Built Diesel Engines.

See Figures 6 and 7

See Diesel Valve Lifter bleed-down.

  1. Remove the air cleaner.
  2.  
  3. Drain the radiator. Loosen the upper bypass hose clamp, remove the thermostat housing bolts, and remove the housing and the thermostat from the intake manifold.
  4.  
  5. Remove the breather pipes from the rocker covers and the air crossover. Remove the air crossover.
  6.  
  7. Disconnect the throttle rod and the return spring. If equipped with cruise control, remove the servo.
  8.  
  9. Remove the hairpin clip at the bell crank 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.
  10.  
  11. Remove the alternator bracket if necessary. On the 350 cu. in. engine, 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.
  12.  
  13. Disconnect the fuel line from the pump and the fuel filter. Remove the fuel filter and bracket.
  14.  
  15. Remove the fuel injection pump and lines.
  16.  
  17. Disconnect and remove the vacuum pump or oil pump drive assembly from the rear of the engine.
  18.  
  19. Remove the intake manifold drain tube.
  20.  
  21. Remove the intake manifold bolts and remove the manifold. Remove the adapter seal. Remove the injection pump adapter.
  22.  



Click image to see an enlarged view

Fig. Fig. 6: Exploded view of a diesel intake manifold assembly



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Fig. Fig. 7: Diesel intake manifold tightening sequence

To install:
  1. Clean the mating surfaces of the cylinder heads and the intake manifold using a putty knife.
  2.  
  3. Coat both sides of the gasket surface that seal the intake manifold to the cylinder heads with G.M. sealer No.1050026 or the equivalent. 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 on the 350 V8 tighten to 15 ft. lbs. (20 Nm) in the sequence shown. Next, tighten all the bolts to 30 ft. lbs. (40 Nm) , in sequence. On the 263 V6 engine. tighten to 15 ft. lbs. (20 Nm) in the sequence shown, then retorque to 41 ft. lbs. (55.5 Nm)
  8.  
  9. Install the intake manifold drain tube and clamp.
  10.  
  11. Install injection pump adapter. See Injection Pump Adapter, Adapter Seal and New Adapter Timing Mark Removal and Installation in Emission Controls . If a new adapter is not being used, skip steps 4 and 9.
  12.  
  13. Install the fuel injection pump.
  14.  
  15. Install the vacuum pump or coil pump drive assembly.
  16.  
  17. Install the remaining components as they were removed.
  18.  


CAUTION
Do not operate the engine without vacuum pump/oil pump assembly in place as this assembly drives the engine oil pump.

 
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