GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Exhaust Manifold

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REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4, 5 and 6

Inline Six With Combination Manifold

Most the inline 6-cylinder engines covered in this guide are equipped with a combination intake/exhaust manifold. Once this combination manifold is removed from the vehicle, the fasteners may be removed and the 2 pieces separated. Certain late-model versions of the inline 250 engine are equipped with an integral intake in which the intake was actually part of the cylinder head. For these engines, which were used in the mid to late 1970's refer to the cylinder head procedure for removal of the integral intake and cylinder head. If your vehicle is equipped with a 250 engine, determine if it has an integral or combination intake by looking for intake manifold mounting bolts and/or a gasket seam between the cylinder head and the intake. If either are found, you have a combination manifold.

For removal and installation procedures regarding the combination intake/exhaust manifold, refer to the intake manifold procedure found earlier in this section.

Inline Six With Integral Intake Manifold/Cylinder Head, Except 1979

See Figure 1

  1. Disconnect the negative battery cable, then remove the air cleaner assembly.
  2.  
  3. Remove the power steering and air pump brackets.
  4.  
  5. Remove the EFE valve bracket.
  6.  
  7. Disconnect the throttle linkage and return spring.
  8.  
  9. Unbolt the exhaust pipe from the flange. The fasteners on the exhaust system are often rusted into place, in order to save your knuckles, spray the fasteners with a penetrating lubricant a few minutes before you attempt to remove them.
  10.  
  11. Unbolt and remove the manifold.
  12.  



Click image to see an enlarged view

Fig. Fig. 1: Exhaust manifold torque sequence-inline 6-cylinder engines equipped with an integral intake/cylinder head

To install:
  1. Position the manifold and gaskets (if used) to the engine, then loosely install the fasteners. Tighten the fasteners to specification using the required sequence (the four end bolts are tightened last).
  2.  
  3. Connect the exhaust pipe to the flange and tighten the retainers.
  4.  
  5. Connect the throttle linkage and return spring.
  6.  
  7. Install the EFE valve bracket.
  8.  
  9. Install the power steering pump and air pump brackets.
  10.  
  11. Install the air cleaner assembly and connect the negative battery cable.
  12.  
  13. Start and run the engine, then check for leaks.
  14.  

Inline Six With Integral Intake Manifold/Cylinder Head, 1979

See Figure 1

  1. Disconnect negative battery cable, then remove the air cleaner assembly.
  2.  
  3. Remove the power steering and/or AIR pumps and brackets, where they are present. (You need not disconnect power steering hoses - just support the pump out of the way).
  4.  

The fasteners on the exhaust system are often rusted into place, in order to save your knuckles, spray the fasteners with a penetrating lubricant a few minutes before you attempt to remove them.

  1. Working from below, with the vehicle safely supported by jackstands, disconnect the exhaust pipe at the manifold and at the catalytic converter bracket near the transmission mount. If the car uses an exhaust manifold mounted converter, disconnect the pipe at the bottom of the converter and remove the converter.
  2.  
  3. Working from above, remove the rear heat shield and accelerator cable bracket.
  4.  
  5. Remove the exhaust manifold bolts, and pull the manifold off the engine.
  6.  
  7. If the manifold is to be replaced, transfer the EFE valve, actuator, and rod assembly to the new part. Otherwise, inspect the manifold as described below.
  8.  
  9. Clean and then inspect the manifold carefully for cracks, and for free operation of the EFE valve. Repair or replace parts, and free up the EFE valve with solvent, as necessary.
  10.  

To install:
  1. Make sure the gasket surface is clean and free of deep scratches. Position a new gasket on the manifold, and then put the manifold in position on the block, and install the bolts hand tight.
  2.  
  3. Torque all bolts in the proper order and to the specified torque.
  4.  
  5. Install the rear heat shield and the accelerator cable bracket.
  6.  
  7. Working from underneath, connect the exhaust pipe at the manifold flange and connect the converter bracket at the transmission mount. If the car has an exhaust manifold converter, first install the converter to the manifold loosely; then attach the exhaust pipe to the converter and align the exhaust system; finally, torque the converter mounting bolts to 15 ft. lbs. (20 Nm), in an X pattern, and torquing in several stages.
  8.  
  9. Working from above, install the power steering and A.I.R. pumps as necessary.
  10.  
  11. Install the air cleaner assembly and connect the negative battery cable.
  12.  



Click image to see an enlarged view

Fig. Fig. 2: Before attempting to loosen exhaust system fasteners, spray them with a penetrating lubricant



Click image to see an enlarged view

Fig. Fig. 3: Loosen the exhaust pipe-to-manifold flange bolts using a deep socket



Click image to see an enlarged view

Fig. Fig. 4: Support the exhaust manifold and remove the retaining bolts



Click image to see an enlarged view

Fig. Fig. 5: Lift the manifold from the vehicle



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Fig. Fig. 6: Make sure the old manifold gaskets are removed from the mating surface and discarded

1964-84 V6 and V8

See Figures 7 and 8

  1. Disconnect the negative battery cable and, if necessary, remove the air cleaner assembly.
  2.  
  3. If equipped with AIR (Air Injection Reaction), remove the air injector manifold assembly. The 1 / 4 in. pipe threads in the manifold are straight threads. Do not use a 1 / 4 in. tapered pipe tap to clean the threads.
  4.  
  5. If applicable, remove the air cleaner preheater shroud.
  6.  
  7. Remove the spark plug wire heat shields. On Mark IV, remove spark plugs.
  8.  
  9. On the left exhaust manifold, disconnect and remove the alternator.
  10.  

The fasteners on the exhaust system are often rusted into place, in order to save your knuckles, spray the fasteners with a penetrating lubricant a few minutes before you attempt to remove them.

  1. Disconnect the exhaust pipe from the manifold and hang it from the frame out of the way.
  2.  
  3. Bend the locktabs and remove the end bolts, then the center bolts. With the retainers removed, carefully pull the manifold from the cylinder head and remove it from the vehicle.
  4.  

A9/16in. thin wall 6-point socket, sharpened at the leading edge and tapped onto the head of the bolt, will simplify bending the locktabs. When installing a new manifold on the right side on 1978-84 V8s you must transfer the heat stove from the old manifold to the new one.

To install:
  1. Thoroughly clean the gasket mating surfaces.
  2.  
  3. Install the exhaust manifold to the engine using new gaskets. Torque all bolts to specification working from the inner bolts towards to the outer bolts.
  4.  
  5. Reconnect the exhaust pipe to the manifold flange, then tighten the fasteners.
  6.  
  7. If removed, install and connect the alternator assembly.
  8.  
  9. For Mark IV, install the spark plugs.
  10.  
  11. Install the spark plug wire head shields.
  12.  
  13. If applicable, install the air cleaner preheater shroud.
  14.  
  15. If equipped, install the air injector manifold assembly.
  16.  
  17. If removed, install the air cleaner assembly.
  18.  
  19. Connect the negative battery cable.
  20.  
  21. Start and run the engine, then check for leaks.
  22.  



Click image to see an enlarged view

Fig. Fig. 7: Exploded view of a common exhaust manifold and hot air shroud assembly



Click image to see an enlarged view

Fig. Fig. 8: Exhaust manifold installation-1980 V6 and V8 engines (most V-engines similar)

V6 Engines, 1985 and Later

See Figures 7 and 8

RIGHT SIDE
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly.
  4.  
  5. Raise and support the vehicle safely using jackstands. If possible, raise the vehicle to a height where access is available both underhood and undervehicle. This will keep you from having to keep raising and lowering it during the procedure.
  6.  

The fasteners on the exhaust system are often rusted into place, in order to save your knuckles, spray the fasteners with a penetrating lubricant a few minutes before you attempt to remove them.

  1. Remove the exhaust pipe bolts, then lower the vehicle, as necessary for underhood access.
  2.  
  3. If equipped with air management valve, disconnect the bracket.
  4.  
  5. If equipped with AIR, disconnect the hoses, then disconnect the pipes to the converter, the cylinder head and the exhaust manifold.
  6.  
  7. Tag and disconnect the spark plug wires.
  8.  
  9. Support the manifold and remove the bolts, then remove the manifold from the vehicle.
  10.  

To install:
  1. Before installing, use a putty knife and clean the gasket mounting surfaces.
  2.  
  3. Install the exhaust manifold to the vehicle using new gaskets, then torque the retaining bolts to the proper specification working from the inner bolts towards the outer bolts.
  4.  
  5. Connect the spark plug wires as noted.
  6.  
  7. If equipped with AIR, connect the hoses, then connect the pipes to the converter, cylinder head and the exhaust manifold.
  8.  
  9. If equipped with an air management valve, connect the bracket.
  10.  
  11. Connect the pipe to the exhaust manifold and tighten the retainers, then remove the jackstands and carefully lower the vehicle.
  12.  
  13. Install the air cleaner assembly and connect the negative battery cable.
  14.  
  15. Start and run the engine, then check for leaks.
  16.  

LEFT SIDE
  1. Disconnect the negative battery cable, and if necessary, remove the air cleaner assembly.
  2.  
  3. Raise and support the vehicle safely using jackstands. If possible, raise the vehicle to a height where access is available both underhood and undervehicle. This will keep you from having to keep raising and lowering it during the procedure.
  4.  

The fasteners on the exhaust system are often rusted into place, in order to save your knuckles, spray the fasteners with a penetrating lubricant a few minutes before you attempt to remove them.

  1. Remove the exhaust pipe bolts, then lower the vehicle, as necessary for underhood access.
  2.  
  3. If equipped with air conditioning, remove the compressor and the rear adjusting brace, then reposition the compressor aside with the lines still connected.
  4.  
  5. If equipped with power steering, remove the power steering pump and the rear lower power steering adjusting brace, then position the pump aside with the lines still connected.
  6.  
  7. Tag and disconnect the spark plug wires from the spark plugs.
  8.  
  9. Support the manifold and remove the retaining bolts, then remove the manifold from the vehicle.
  10.  

To install:
  1. Before installing, use a putty knife and clean the gasket mounting surfaces.
  2.  
  3. Install the exhaust manifold to the vehicle using new gaskets, then torque the retaining bolts to the proper specification working from the inner bolts towards the outer bolts.
  4.  
  5. Connect the spark plug wires as noted.
  6.  
  7. If equipped with power steering, reposition and secure the pump along with the rear lower adjusting brace.
  8.  
  9. If equipped with A/C, reposition and secure the compressor along with the rear adjusting brace.
  10.  
  11. Connect the exhaust pipe to the manifold and tighten the retainers, then remove the jackstands and carefully lower the vehicle.
  12.  
  13. If removed, install the air cleaner assembly.
  14.  
  15. Connect the negative battery cable.
  16.  
  17. Start and run the engine, then check for leaks.
  18.  

V8 Engines, 1985 and Later

See Figures 7 and 8

RIGHT SIDE
  1. Disconnect the negative battery cable and remove the air cleaner assembly.
  2.  
  3. Raise and support the vehicle safely using jackstands. If possible, raise the vehicle to a height where access is available both underhood and undervehicle. This will keep you from having to keep raising and lowering it during the procedure.
  4.  

The fasteners on the exhaust system are often rusted into place, in order to save your knuckles, spray the fasteners with a penetrating lubricant a few minutes before you attempt to remove them.

  1. Remove the exhaust pipe bolts, then lower the vehicle, as necessary for underhood access.
  2.  
  3. Tag and disconnect the spark plug wires from the spark plugs, the vacuum hoses from the carbon canister and, if equipped, the AIR hose(s).
  4.  
  5. If equipped, loosen the alternator belt, then remove the lower alternator bracket and the AIR valve. Disconnect the converter's AIR pipe from the back of the manifold.
  6.  
  7. Support the manifold and remove the retaining bolts, then remove the manifold from the vehicle.
  8.  

To install:
  1. Before installing, use a putty knife and clean the gasket mounting surfaces.
  2.  
  3. Install the exhaust manifold to the vehicle using new gaskets, then torque the retaining bolts to the proper specification working from the inner bolts towards the outer bolts.
  4.  
  5. If equipped, connect the AIR pipe to the back of the manifold, then install the AIR valve and the lower alternator bracket. Adjust the drive belt tension.
  6.  
  7. Connect the spark plug wires as noted.
  8.  
  9. Connect the exhaust pipe to the manifold and tighten the retainers, then remove the jackstands and carefully lower the vehicle.
  10.  
  11. Install the air cleaner assembly and connect the negative battery cable.
  12.  
  13. Start and run the engine, then check for leaks.
  14.  

LEFT SIDE
  1. Disconnect the negative battery cable and, if necessary, remove the air cleaner assembly.
  2.  
  3. Raise and support the vehicle safely using jackstands. If possible, raise the vehicle to a height where access is available both underhood and undervehicle. This will keep you from having to keep raising and lowering it during the procedure.
  4.  

The fasteners on the exhaust system are often rusted into place, in order to save your knuckles, spray the fasteners with a penetrating lubricant a few minutes before you attempt to remove them.

  1. Remove the exhaust pipe bolts, then lower the vehicle, as necessary for underhood access.
  2.  
  3. Tag and disconnect the spark plug wires from the plugs.
  4.  
  5. If equipped, disconnect the AIR hose.
  6.  
  7. If equipped with air conditioning, loosen the bracket at the front of the head, then remove the rear bracket and the compressor. Position the compressor aside with the lines intact.
  8.  
  9. If equipped with power steering, remove the power steering pump and the lower adjusting bracket. Position the pump aside with the lines intact.
  10.  
  11. Support the manifold and remove the retaining bolts, then remove the wire loom holder and the valve cover and remove the manifold from the vehicle.
  12.  

To install:
  1. Before installing, use a putty knife and clean the gasket mounting surfaces.
  2.  
  3. Install the exhaust manifold and the wire loom holder to the vehicle using new gaskets, then torque the retaining bolts to the proper specification working from the inner bolts towards the outer bolts.
  4.  
  5. If equipped, reposition and secure the power steering pump, along with the lower adjusting bracket.
  6.  
  7. If equipped, reposition and secure the A/C compressor, along with the front and rear brackets.
  8.  
  9. If equipped, connect the AIR hose.
  10.  
  11. Connect the spark plug wires as noted during removal.
  12.  
  13. Connect the exhaust pipe to the manifold and tighten the retainers, then remove the jackstands and carefully lower the vehicle.
  14.  
  15. If removed, install the air cleaner assembly.
  16.  
  17. Connect the negative battery cable.
  18.  
  19. Start and run the engine, then check for leaks.
  20.  

Diesel Engines
LEFT SIDE
  1. Disconnect the negative battery cable and remove the air cleaner assembly.
  2.  
  3. Remove the alternator lower bracket.
  4.  
  5. Raise and support the vehicle safely using jackstands. If possible, raise the vehicle to a height where access is available both underhood and undervehicle. This will keep you from having to keep raising and lowering it during the procedure.
  6.  

The fasteners on the exhaust system are often rusted into place, in order to save your knuckles, spray the fasteners with a penetrating lubricant a few minutes before you attempt to remove them.

  1. Remove the exhaust crossover pipe, then lower the vehicle, as necessary for underhood access.
  2.  
  3. Support the manifold and remove the retaining bolts, then remove the manifold from the vehicle.
  4.  

To install:
  1. Before installing, use a putty knife and clean the gasket mounting surfaces.
  2.  
  3. Install the exhaust manifold to the engine using new gaskets, then tighten the retaining bolts working from the inner bolts towards the outer bolts.
  4.  
  5. Install the crossover pipe and tighten the retainers, then remove the jackstands and carefully lower the vehicle.
  6.  
  7. Install the alternator lower bracket.
  8.  
  9. Install the air cleaner assembly and connect the negative battery cable.
  10.  
  11. Start and run the engine, then check for leaks.
  12.  

RIGHT SIDE
  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the safely using jackstands.
  4.  
  5. Remove the crossover pipe.
  6.  
  7. Disconnect the exhaust pipe.
  8.  
  9. Remove the right front wheel.
  10.  
  11. Support the manifold and remove the retaining bolts, then lower and remove the manifold from under the vehicle.
  12.  

To install:
  1. Before installing, use a putty knife and clean the gasket mounting surfaces.
  2.  
  3. Install the exhaust manifold to the engine using new gaskets, then tighten the retaining bolts working from the inner bolts towards the outer bolts.
  4.  
  5. Install the right front wheel.
  6.  
  7. Connect the exhaust pipe and install the crossover pipe.
  8.  
  9. Remove the jackstands and carefully lower the vehicle.
  10.  
  11. Connect the negative battery cable.
  12.  

 
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