GM Full Size Vans 1987-1997 Repair Guide

Exhaust Manifold

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REMOVAL & INSTALLATION



4.3L Engines

See Figure 1

On some engines, tab locks are used on the front and rear pairs of bolts on each exhaust manifold. When removing the bolts, straighten the tabs from beneath the van using a suitable tool. When installing the tab locks, bend the tabs against the sides of the bolt, not over the top of the bolt.

1987-95 MODELS
  1. Disconnect the negative battery cable. Remove the air cleaner assembly.
  2.  
  3. Remove the engine cover.
  4.  



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Fig. Fig. 1: Exhaust manifold - 4.3L engine



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Fig. Fig. 2: Loosen the retainers and disconnect the exhaust pipe from the manifold



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Fig. Fig. 3: Except for 1996-97 models, disconnect the heat stove tube from the exhaust manifold

  1. Raise the vehicle and support it with jackstands.
  2.  
  3. Remove the hot air shroud, (if so equipped). Disconnect the exhaust pipe at the manifold.
  4.  
  5. Lower the van.
  6.  
  7. Disconnect the O 2 sensor wire on the left side manifold. Do not remove the sensor unless you intend to replace it.
  8.  
  9. Disconnect the rear power steering pump bracket at the left manifold.
  10.  
  11. Remove the heat stove pipe on the right side manifold.
  12.  
  13. Remove the AIR hose at the check valve, if equipped.
  14.  
  15. Remove the manifold bolts and remove the manifold(s). Some models have lock tabs on the front and rear manifold bolts which must be removed before removing the bolts. These tabs can be bent with a drift pin.
  16.  



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Fig. Fig. 4: Once the tab washers are flattened, loosen and remove the manifold retaining bolts ...:



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Fig. Fig. 5: ... then carefully remove the manifold from the van

To install:
  1. Clean both the manifold and cylinder block mating surfaces and install the manifold. Install the flat washers and then the tab washers and insert the bolts. Tighten the two center bolts to 26 ft. lbs. (36 Nm); the outside bolts to 20 ft. lbs. (28 Nm) and then bend the tab washers against the bolt heads.
  2.  
  3. Install the AIR hose at the check valve, if equipped.
  4.  
  5. Install the heat stove pipe on the right side manifold.
  6.  
  7. Connect the rear power steering pump bracket at the left manifold.
  8.  
  9. Connect the O 2 sensor wire on the left side manifold.
  10.  
  11. Raise the van and support it with jackstands.
  12.  
  13. Connect the exhaust pipe at the manifold. Install the hot air shroud.
  14.  
  15. Lower the van.
  16.  
  17. Install the air cleaner. Connect the negative battery cable.
  18.  
  19. Install the engine cover.
  20.  

1996-97 MODELS

See Figures 2 and 3

  1. Disconnect the negative battery cable. Remove the air cleaner assembly.
  2.  
  3. Remove the engine cover.
  4.  
  5. If applicable, remove the coolant recovery reservoir.
  6.  
  7. Raise the vehicle and support it with jackstands.
  8.  
  9. Remove the hot air shroud, (if so equipped). Disconnect the exhaust pipe at the manifold.
  10.  
  11. Lower the van.
  12.  
  13. If necessary, remove the EGR inlet pipe from the left manifold.
  14.  
  15. Unfasten the manifold retainers and remove the manifold.
  16.  



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Fig. Fig. 6: Exploded view of the heat shields - 1996-97 4.3L engine



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Fig. Fig. 7: Exhaust manifold fasteners locations - 1996-97 4.3L engine

To install:
  1. Clean the manifold-to-cylinder head mating surfaces.
  2.  
  3. Install the manifold and tighten the retainers in the following sequence:

    Bolts on the center exhaust tube: 11 ft. lbs. (15 Nm)
     
    Bolts on the front and rear exhaust tubes: 22 ft. lbs. (30 Nm)
     

  4.  
  5. Bend the tab washers over the bolts.
  6.  
  7. If removed, install the EGR inlet pipe.
  8.  
  9. Raise the vehicle and support it with jackstands.
  10.  
  11. Install the exhaust pipe at the manifold.
  12.  
  13. Install the hot air shroud, If equipped.
  14.  
  15. Lower the vehicle.
  16.  
  17. Install the engine cover.
  18.  
  19. If removed, install the coolant recovery reservoir.
  20.  
  21. Install the air cleaner and intake duct.
  22.  
  23. Connect the negative battery cable.
  24.  

5.0L and 5.7L Engines

See Figure 4

On some engines, tab locks are used on the front and rear pairs of bolts on each exhaust manifold. When removing the bolts, straighten the tabs from beneath the van using a suitable tool. When installing the tab locks, bend the tabs against the sides of the bolt, not over the top of the bolt.

  1. Disconnect the negative battery cable. Remove the air cleaner.
  2.  



Click image to see an enlarged view

Fig. Fig. 8: Exhaust manifold - 5.0L and 5.7L engines

  1. Disconnect the negative battery cable and remove the engine cover.
  2.  
  3. If necessary, remove the air cleaner assembly and coolant recovery reservoir.
  4.  
  5. On 1996-97 models, disconnect the EGR inlet tube and the oil dipstick tube.
  6.  
  7. If necessary, tag and disconnect the ignition wires from the spark plugs.
  8.  
  9. Raise the van and support it with jackstands.
  10.  
  11. Remove the hot air shroud, (if so equipped). Disconnect the exhaust pipe at the manifold.
  12.  
  13. Lower the van.
  14.  
  15. Disconnect the O 2 sensor wire on the left side manifold. Do not remove the sensor unless you intend to replace it.
  16.  
  17. On some models it may be necessary to remove the left side floor panel to gain access to the exhaust manifold.
  18.  
  19. Remove the heat stove pipe on the right side manifold.
  20.  
  21. Disconnect the rear power steering pump bracket at the left manifold.
  22.  
  23. Remove the dipstick tube bracket on the right manifold.
  24.  
  25. Remove the manifold bolts and remove the manifold(s). Some models have locktabs on the front and rear manifold bolts which must be removed before removing the bolts. These tabs can be bent with a drift pin or needlenose pliers.
  26.  



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Fig. Fig. 9: Remove the exhaust pipe from the manifold



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Fig. Fig. 10: Use a pair of needlenose pliers to bend back the locktabs on the exhaust manifold



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Fig. Fig. 11: Loosen and remove the exhaust manifold bolts



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Fig. Fig. 12: Remove the exhaust manifold

To install:
  1. Clean both the manifold and cylinder block mating surfaces and install the manifold. Install the flat washers and then the tab washers and insert the bolts. On 1987-95 models, tighten the two center bolts to 26 ft. lbs. (36 Nm); the outside bolts to 20 ft. lbs. (28 Nm) and then bend the tab washers against the bolt heads.
  2.  

On 1996-97 models, tighten the bolts in two passes in the sequence illustrated. On the first pass, tighten the bolts to 11 ft. lbs. (15 Nm) and on the second pass to 22 ft. lbs. (30 Nm).

  1. Install the dipstick tube bracket on the right manifold.
  2.  
  3. If removed install the EGR inlet tube.
  4.  
  5. If removed, connect the ignition wires to the spark plugs.
  6.  
  7. Install the left floor panel, if removed.
  8.  
  9. Connect the rear power steering pump bracket at the left manifold.
  10.  
  11. Install the heat stove pipe on the right side manifold.
  12.  
  13. Connect the O 2 sensor wire on the left side manifold.
  14.  
  15. Raise the van and support it with jackstands.
  16.  
  17. Connect the exhaust pipe at the manifold. Install the hot air shroud.
  18.  
  19. Lower the van.
  20.  
  21. Install the air cleaner assembly and coolant recovery reservoir.
  22.  
  23. Connect the negative battery cable.
  24.  
  25. Install the engine cover.
  26.  

7.4L Engines
RIGHT SIDE

See Figure 5

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the engine cover.
  4.  
  5. Remove the heat stove pipe, if applicable.
  6.  
  7. Remove the dipstick tube.
  8.  
  9. Disconnect the AIR hose at the check valve, if equipped.
  10.  
  11. Remove the spark plugs.
  12.  
  13. Disconnect the exhaust pipe at the manifold.
  14.  
  15. Remove the manifold bolts and spark plug heat shields.
  16.  
  17. Remove the manifold.
  18.  



Click image to see an enlarged view

Fig. Fig. 13: Exploded view of the exhaust manifold mounting - 1996-97 model shown (others similar)

To install:
  1. Clean the mating surfaces.
  2.  
  3. Clean the stud threads.
  4.  
  5. Install the manifold and bolts. Tighten the bolts to 40 ft. lbs. (54 Nm) and if equipped with nuts (late model vehicles) tighten those to 22 ft. lbs. (30 Nm) starting from the center bolts and working towards the outside.
  6.  
  7. Connect the exhaust pipe at the manifold.
  8.  
  9. Install the spark plugs.
  10.  
  11. Connect the AIR hose at the check valve, if equipped.
  12.  
  13. Install the dipstick tube.
  14.  
  15. Install the heat stove pipe, if applicable.
  16.  
  17. Connect the battery.
  18.  
  19. Install the engine cover.
  20.  

6.2L and 6.5L Diesel Engines
RIGHT SIDE

See Figures 6 and 7

  1. Disconnect the batteries.
  2.  
  3. Jack up the vehicle and safely support it with jackstands.
  4.  



Click image to see an enlarged view

Fig. Fig. 14: Exhaust manifold (right side) - 6.2L engines



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Fig. Fig. 15: Exhaust manifold (right side) - 6.5L engine

  1. Remove the engine cover.
  2.  
  3. Disconnect the exhaust pipe from the manifold flange and lower the van.
  4.  
  5. Disconnect the glow plug wires.
  6.  
  7. Remove the air cleaner duct bracket.
  8.  
  9. Remove the glow plug wires.
  10.  
  11. Remove the turbocharger on the 6.5L, if equipped.
  12.  
  13. Remove the manifold bolts and remove the manifold.
  14.  

To install:
  1. Clean all mating surfaces and install the manifold. Tighten the bolts to 26 ft. lbs. (35 Nm).
  2.  
  3. Install the turbocharger on the 6.5L, if equipped.
  4.  
  5. Install the glow plugs.
  6.  
  7. Install the air cleaner duct bracket.
  8.  
  9. Connect the glow plug wires.
  10.  
  11. Raise the vehicle and support it with jackstands.
  12.  
  13. Connect the exhaust pipe to the manifold flange and lower the van.
  14.  
  15. Connect the batteries.
  16.  
  17. Install the engine cover.
  18.  

LEFT SIDE

See Figure 8

  1. Disconnect the batteries, negative cable first.
  2.  
  3. Remove the engine cover.
  4.  
  5. Remove the dipstick tube nut, and remove the dipstick tube.
  6.  



Click image to see an enlarged view

Fig. Fig. 16: Exhaust manifold (left side) - 6.2L and 6.5L engines

  1. Disconnect the glow plug wires.
  2.  
  3. Raise the vehicle and safely support it with jackstands.
  4.  
  5. Disconnect the exhaust pipe at the manifold flange.
  6.  
  7. Remove the manifold bolts. Remove the manifold from underneath the van.
  8.  

To install:
  1. Install the manifold and tighten the bolts to 26 ft. lbs. (35 Nm).
  2.  
  3. Connect the exhaust pipe to the manifold flange.
  4.  
  5. Lower the vehicle and connect the glow plug wires.
  6.  
  7. Install the dipstick tube and tighten the nut.
  8.  
  9. Connect the batteries, positive cable first.
  10.  
  11. Install the engine cover.
  12.  

 
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