Buick Regal 1997-2000

Exhaust Manifold

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Removal & Installation



3.1L And 3.4L (VIN E) Engines
Left Side (Front)
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner duct.
  4.  
  5. Drain the coolant into a suitable container.
  6.  
  7. Remove the right side engine mount strut bracket.
  8.  
  9. Disconnect the upper radiator hose from the engine.
  10.  
  11. Remove the automatic transaxle vacuum modulator pipe.
  12.  
  13. Remove the thermostat bypass pipe.
  14.  
  15. Remove the exhaust crossover pipe heat shield and then remove the crossover pipe.
  16.  
  17. Remove the left side (front) exhaust manifold heat shield bolts and remove the heat shield.
  18.  
  19. Remove the manifold bolts and nuts and remove the manifold. Discard the gasket.
  20.  

To install:



Click image to see an enlarged view

Fig. Left side (front) exhaust manifold and heat shield-3.1L engine shown, 3.4L (VIN E) is similar

  1. Clean all parts well. Clean the manifold and cylinder head sealing surfaces.
  2.  
  3. Using a new gasket, position the exhaust manifold to the cylinder head. Install the bolts and nuts. Torque to 12 ft. lbs. (16 Nm).
  4.  
  5. Install the remaining components in the reverse order of the removal process.
  6.  

Right Side (Rear)
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner duct.
  4.  
  5. Drain the coolant.
  6.  
  7. Disconnect the upper radiator hose from the engine.
  8.  
  9. Remove the upper radiator hose from the engine.
  10.  
  11. Remove the automatic transaxle vacuum modulator pipe.
  12.  
  13. Remove the exhaust crossover pipe heat shield and then remove the crossover pipe.
  14.  
  15. Detach the oxygen sensor electrical connector.
  16.  
  17. Raise and safely support the vehicle.
  18.  
  19. Disconnect the three-way catalytic converter pipe from the right side (rear) manifold.
  20.  
  21. Remove the automatic transaxle fluid filler tube and move the tube aside.
  22.  
  23. Remove the EGR tube from the rear exhaust manifold.
  24.  
  25. Remove the oxygen sensor.
  26.  
  27. Remove the right side (rear) exhaust manifold upper heat shield bolts and remove the upper heat shield.
  28.  
  29. Remove lower heat shield bolts and remove the lower heat shield.
  30.  
  31. Remove the manifold and nuts and remove the manifold. Discard the gasket.
  32.  

To install:



Click image to see an enlarged view

Fig. Right side (rear) exhaust manifold and lower heat shield-3.1L engine shown, 3.4L (VIN E) is similar

  1. Clean all parts well. Clean the manifold and cylinder head sealing surfaces.
  2.  
  3. Using a new gasket, position the exhaust manifold to the cylinder head. Install the bolts and nuts. Torque to 12 ft. lbs. (16 Nm).
  4.  
  5. Install the heat shields and tighten the bolts to 89 inch lbs. (10 Nm).
  6.  
  7. Install the remaining components in the reverse order of the removal process.
  8.  

3.4L (VIN X) Engine
Left Side (Front)
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner ducts.
  4.  
  5. Remove the exhaust crossover pipe.
  6.  
  7. Remove the electric cooling fan assembly.
  8.  
  9. Remove the exhaust manifold retaining nuts, the heat shield and the manifold. Discard the gasket.
  10.  



Click image to see an enlarged view

Fig. Exploded view of the exhaust manifold and heat shield; left side shown, right side similar-3.4L (VIN X) engine

To install:

  1. Using a new gasket, position the exhaust manifold with the heat shield to the cylinder head. Install the nuts and torque to 115 inch lbs. (13 Nm).
  2.  
  3. Install the remaining components in the reverse order of the removal process.
  4.  

Right Side (Rear)

CAUTION
This is a complicated procedure requiring numerous components to be removed and the subframe containing the engine and transaxle to be loosened and lowered for clearance. This is not a job for the inexperienced or ill-equipped. Be very sure that the exhaust manifold and/or manifold gasket really needs to be replaced before attempting this procedure. Be very sure of the lifting and jacking equipment you have available before attempting this procedure or the vehicle could be damaged and you could be injured. In addition, the factory specifies that whenever frame to body bolts are loosened or removed, they must be replaced with new bolts and retainers. Procure the bolts before beginning this procedure. Failure to replace frame to body bolts and retainers may result in damage to the frame, powertrain or suspension.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner duct.
  4.  
  5. Remove the exhaust crossover pipe.
  6.  
  7. Disconnect the Exhaust Gas Recirculation (EGR) tube from the exhaust manifold.
  8.  
  9. Raise and safely support the vehicle.
  10.  
  11. Remove the front pipe and the converter assembly.
  12.  
  13. Disconnect the oxygen sensor electrical connector from the wiring harness. Note that the oxygen sensor uses a permanently attached pigtail and connector. This pigtail should not be removed from the oxygen sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor. Keep the connector free of grease and contaminates.
  14.  
  15. Remove the exhaust pipe front heat shield.
  16.  
  17. Remove the alternator rear brace.
  18.  
  19. Remove the automatic transaxle dipstick tube.
  20.  
  21. Remove the intermediate steering shaft lower pinch bolt and disengage the intermediate shaft from the rack and pinion steering gear assembly.
  22.  
  23. Remove the exhaust manifold nuts.
  24.  
  25. Install a suitable lifting/jacking device to support the rear of the subframe.
  26.  
  27. Remove the rear subframe bolts. Discard the bolts. They must be replaced with new bolts.
  28.  
  29. Using the lifting/jacking device, lower the rear of the subframe not more that 4 inches.
  30.  


WARNING
Do not lower the frame more than 4 inches.

  1. Remove the rack and pinion steering gear heat shield.
  2.  
  3. Remove the exhaust manifold heat shield.
  4.  
  5. Remove the exhaust manifold. Discard the gasket.
  6.  

To install:

  1. Clean all parts well, especially the sealing surfaces between the manifold and the cylinder head.
  2.  
  3. Using a new gasket, position the exhaust manifold with the heat shield to the cylinder head. Install the nuts and torque to 115 inch lbs. (13 Nm).
  4.  
  5. Install the remaining components in the reverse order of the removal process, paying attention to the following points;
    1. When using the lifting/jacking device, raise the frame rear until the frame contacts the body. Install new replacement body bolts. Note the following:
    2.  
    3. Position the frame with aid of an assistant. A 19 / 32 (15mm) guide pin or drill bit can be inserted into the alignment holes located on the right side.
    4.  
    5. Proper clamping by the mount depends on clean and dry surfaces. If the frame isolator bolt does not screw in smoothly, it may be necessary to run a tap through the cage nut in the body to remove foreign material. Take care that the tap does not punch through the underbody. If the cage nut cannot be used, the cage nut retainer spot welds will have to be chiseled away with an air chisel, the cage nut replaced and the retainer welded back into its original location. Clean and prime the area with catalyzed primer to protect the area from corrosion.
    6.  

  6.  
  7. Torque the four new frame isolator bolts to 133 ft. lbs. (180 Nm). Do not over-tighten the body mounts; a collapsed spacer or stripped bolt may result. Tighten in the following manner:
    1. RH Rear, first
    2.  
    3. RH Front, second
    4.  
    5. LH Rear, third
    6.  
    7. LH Front, fourth
    8.  

  8.  
  9. Connect the catalytic converter to the rear exhaust.
  10.  
  11. Attach the oxygen sensor wiring connector.
  12.  


CAUTION
When installing the intermediate shaft, make sure the shaft is seated prior to pinch bolt installation. If the pinch bolt is inserted into the coupling before shaft installation, the two mating shafts may disengage, with a loss of steering.

  1. Connect the intermediate steering shaft to the rack and pinion steering assembly stub shaft. Verify that the two shafts are properly coupled. Insert the pinch bolt and torque carefully to 35 ft. lbs. (47 Nm).
  2.  
  3. Install the remaining components in the reverse order of the removal process.
  4.  

3.5L Engine
Left Side (Front)


Click image to see an enlarged view

Fig. Left side (front) exhaust manifold-3.5L (VIN H) engine

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the cosmetic/acoustic engine cover.
  4.  
  5. Remove the engine mount strut and bracket.
  6.  
  7. Remove the engine cooling fans.
  8.  
  9. Drain the coolant from the engine into a suitable container.
  10.  
  11. Remove both radiator hoses and disconnect the automatic transaxle cooling lines from the radiator.
  12.  
  13. Remove the radiator.
  14.  
  15. Remove the alternator. Please see Section 2.
  16.  
  17. Remove the exhaust manifold heat shield retaining bolts and remove the heat shield.
  18.  
  19. Remove the dipstick and tube.
  20.  
  21. Locate the AIR control valve just over the exhaust crossover and disconnect the vacuum tube and the feed pipe nut from the exhaust manifold. Remove the AIR valve retaining bolt and remove the valve from the engine mount strut bracket.
  22.  
  23. Loosen the exhaust manifold bolts.
  24.  
  25. Remove the exhaust manifold to crossover pipe flange retaining bolts and the flange gasket. Discard the flange gasket.
  26.  
  27. Remove the exhaust manifold bolts and separate the manifold from the cylinder head. Discard the gaskets.
  28.  

To install:

  1. Clean all parts well, especially the sealing surfaces between the manifold and the cylinder head.
  2.  
  3. Install a new manifold to crossover flange gasket onto the manifold flange, then tighten the manifold-to-crossover pipe flange bolts to 18 ft. lbs. (25 Nm).
  4.  
  5. Using a new gasket, position the exhaust manifold to the cylinder head. Install the nuts and torque to 18 ft. lbs. (25 Nm). The exhaust crossover fasteners are tightened to 15 ft. lbs. (20 Nm).
  6.  
  7. Install the remaining components in the reverse order of the removal process.
  8.  

Right Side (Rear)

WARNING
This is a difficult and complicated procedure. The entire engine/transaxle/subframe assembly must be removed to access the rear exhaust manifold. Be very sure the exhaust manifold and/or gasket really needs to be serviced. The factory recommended procedure for removing this engine is a lengthy and difficult procedure requiring special lifting and support equipment. The steering shaft must be separated and the vehicle subframe must be loosened and lowered. The vehicle's powertrain assembly, including the entire engine/transaxle/subframe assembly is lowered out of the bottom of the engine compartment and then the vehicle is lifted up away from the removed powertrain. Careful work is required for reassembly. This is not a job for the inexperienced or ill-equipped.



Click image to see an enlarged view

Fig. Right side (rear) exhaust manifold-3.5L (VIN H) engine

  1. Remove the engine/transaxle/subframe from the vehicle using the procedure found in this section.
  2.  
  3. With the powertrain assembly secure on a frame table or other suitable, safe work stand and the body lifted and secured away from the powertrain assembly, remove the right side (rear) exhaust manifold crossover pipe bolts from the left side (front) exhaust manifold.
  4.  
  5. Disconnect the EGR valve pipe from the exhaust crossover pipe.
  6.  
  7. Remove the right side (rear) exhaust manifold retaining bolts and separate the manifold from the cylinder head. Discard the gasket.
  8.  

To install:

  1. Clean all parts well, especially the sealing surfaces between the manifold and the cylinder head. This is also a good time to remove the oxygen sensor and inspect for excessive deposits. Replace it if necessary. Inspect the exhaust manifold studs and replace if necessary.
  2.  
  3. Install a new manifold to crossover flange gasket onto the manifold flange, then tighten the manifold to crossover pipe flange bolts to 18 ft. lbs. (25 Nm).
  4.  
  5. Position a new gasket onto the exhaust manifold, install the bolts and place the manifold, gasket and bolts, as an assembly, in position on the cylinder head. Install the nuts and torque to 18 ft. lbs. (25 Nm). The exhaust crossover fasteners are tightened to 15 ft. lbs. (20 Nm).
  6.  
  7. Install the remaining components in the reverse order of the removal process. Please see the engine installation procedure in this section.
  8.  

3.8L Engine
Front Manifold
  1. Disconnect the negative battery cable.
  2.  
  3. Tag for identification and remove the front side spark plug wires.
  4.  
  5. Remove the exhaust crossover heat shield nuts and remove the shield.
  6.  
  7. Remove the nuts and bolts from the exhaust crossover and remove the crossover pipe.
  8.  
  9. Remove the exhaust manifold nuts and bolts. Remove the manifold. Discard the gasket.
  10.  



Click image to see an enlarged view

Fig. Left side (front) exhaust manifold-3.8L engine

To install:

  1. Clean all parts well, especially the sealing surfaces between the manifold and the cylinder head.
  2.  
  3. Using a new gasket, position the exhaust manifold to the cylinder head. Install the nuts and torque to 22 ft. lbs. (30 Nm). Tighten the exhaust crossover fasteners to 15 ft. lbs. (20 Nm).
  4.  
  5. Install the remaining components in the reverse order of the removal process.
  6.  

Right Side (Rear)
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the EGR outlet pipe from the manifold.
  4.  
  5. Remove the exhaust crossover heat shield nuts and remove the shield.
  6.  
  7. Remove the nuts and bolts from the exhaust crossover and remove the crossover pipe.
  8.  
  9. Raise and safely support the vehicle.
  10.  
  11. Disconnect the three-way catalytic converter pipe from the manifold.
  12.  
  13. Disconnect the oxygen sensor lead.
  14.  
  15. Remove the exhaust manifold nuts and bolts. Remove the manifold. Discard the gasket.
  16.  



Click image to see an enlarged view

Fig. Right side (rear) exhaust manifold-3.8L engine

To install:

  1. Clean all parts well, especially the sealing surfaces between the manifold and the cylinder head.
  2.  
  3. Using a new gasket, position the exhaust manifold to the cylinder head. Install the nuts and torque to 22 ft. lbs. (30 Nm). Tighten the exhaust crossover fasteners to 15 ft. lbs. (20 Nm).
  4.  
  5. Install the remaining components in the reverse order of the removal process.
  6.  

 
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