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Eric, Automotive Repair Shop Manager
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Experience:  20+ yrs. experience as repair shop manager and technician.
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99 pontiac montana: Do i just remove and replace the head gaskets

Resolved Question:

Yes how do i replace the head gaskets on a 99 pontiac montana. I have an idea. Do i just remove and replace the head gaskets.or do i have to line something like rje crank and cam before assembly.
Submitted: 4 years ago.
Category: Pontiac
Expert:  Eric replied 4 years ago.

Hi,

 

Below are directions to remove both heads:\

 

EXHAUST MANNIFOLD:

 

3.4L Engine

LEFT SIDE (FRONT)

  1. Disconnect the negative battery cable.
  2. Drain and recycle the engine coolant.
  3. Remove the air cleaner duct.
  4. Remove the right engine mount strut bracket.
  5. Disconnect the upper radiator hose from the engine.
  6. Remove the automatic transaxle vacuum modulator pipe.
  7. Remove the thermostat bypass pipe.
  8. Remove the exhaust crossover pipe heat shield, and remove the exhaust crossover pipe bolts to the left exhaust manifold.
  9. Unfasten the left exhaust manifold heat shield bolts, then remove the heat shield.
  10. Remove the left exhaust manifold nuts, then remove the left exhaust manifold and gasket.
  11. Clean the mating surfaces with a suitable solvent.

 

See Figures 2 and 3

Click image to see an enlarged view

Fig. Fig. 2: Exhaust manifold heat shield removal and installation



Click image to see an enlarged view

Fig. Fig. 3: Exploded view of the exhaust manifold

 

To install:

  1. Install the exhaust manifold gasket, the exhaust manifold, and the manifold nuts.
  2. Liberally coat the fasteners for the manifold with a suitable anti-seize compound. Tighten the nuts to 12 ft. lbs. (16 Nm).
  3. The remainder of installation is the reverse of the removal procedure.


RIGHT SIDE (REAR)

  1. Disconnect the negative battery cable.
  2. Remove the air cleaner duct.
  3. Drain and recycle the engine coolant.
  4. Disconnect the upper radiator hose from the engine
  5. Remove the automatic transaxle vacuum modulator pipe, then pull the dipstick out.
  6. Remove the thermostat bypass pipe.
  7. Remove the exhaust crossover pipe heat shield, and then the bolts from the right (rear) exhaust manifold.
  8. Detach the oxygen sensor electrical connector.
  9. Raise and safely support the vehicle securely on jackstands.
  10. Remove the three-way catalytic converter pipe from the right (rear) exhaust manifold.
  11. Remove the automatic transaxle fluid filler tube. Move the filler tube aside.
  12. Remove the EGR tube and the oxygen sensor from the exhaust manifold.
  13. Unfasten the heat shield bolts, then remove the upper and lower heat shields.

 

See Figures 4 and 5

Click image to see an enlarged view

Fig. Fig. 4: Remove the upper heat shield ...



Click image to see an enlarged view

Fig. Fig. 5: ... then remove the lower heat shield

 

  1. Remove the exhaust manifold nuts, then remove the manifold and gasket.

 

See Figure 6

Click image to see an enlarged view

Fig. Fig. 6: After the heat shields are removed, unfasten the retainers and remove the exhaust manifold

 

To install:

Before installation, liberally coat the fasteners for the manifold, with a suitable anti-seize compound.

  1. Install the exhaust manifold gasket, the exhaust manifold, and the manifold nuts.
  2. Tighten the exhaust manifold nuts to 12 ft. lbs. (16 Nm).
  3. Install the heat shields. Tighten the upper and lower heat shield nuts to 89 inch lbs. (10 Nm)
  4. The remainder of installation is the reverse of the removal procedure

 

 

INTAKE MANIFOLD:

3.4L Engine

This engine uses a sequential multiport fuel injection system. During installation, you must attach the injector electrical connectors to their appropriate fuel injector, or exhaust emissions and engine performance may be seriously affected.

UPPER MANIFOLD

  1. Disconnect the negative battery cable.
  2. Drain and recycle the engine coolant.
  3. Properly relieve the fuel system pressure, as outlined in .
  4. Remove the fuel injector sight shield.
  5. Remove the air cleaner duct.
  6. Remove the accelerator control and cruise control cables, with the bracket, from the throttle body.
  7. Tag and detach the wiring harness connectors from the throttle body. Lay the harness aside.
  8. Remove the thermostat bypass pipe coolant hoses from the throttle body.
  9. Label the vacuum lines and disconnect them from the connections at the throttle body.
  10. Tag and disconnect the left side (front) spark plug wires, and set them aside.
  11. Remove the ignition coil bracket with the coils, the purge solenoid and the vacuum canister solenoid.
  12. Remove the Manifold Absolute Pressure (MAP) sensor and bracket.

 

See Figure 2

Click image to see an enlarged view

Fig. Fig. 2: Exploded view of the upper intake manifold assembly-3.4L engine

 

  1. Tag and disconnect the vacuum hose connections from the upper intake manifold.
  2. Remove the rear alternator brace.
  3. Remove the Exhaust Gas Recirculation (EGR) valve.
  4. Unfasten the upper intake manifold nuts and bolts, then remove the upper intake manifold.
  5. Remove the upper intake gasket, be careful not to mar or scratch the sealing surfaces while cleaning them with degreaser.

 

On some applications, you may want to remove the throttle body.

  1. Installation is the reverse of the removal procedure. Make sure to tighten all retainers evenly and securely. Attach all electrical connections and vacuum lines as tagged during removal. Fill all fluids to their proper levels, and check for leaks.


LOWER MANIFOLD

  1. Disconnect the negative battery cable.
  2. Drain and recycle the engine coolant.
  3. Properly relieve the fuel system pressure
  4. Remove the upper intake manifold, as outlined in this section.
  5. Remove the left (front) and right (rear) rocker arm covers. Use a backup wrench to disconnect the fuel feed and return pipe from the fuel injector rail.
  6. Remove the fuel rail assembly. For more details, refer to of this repair guide.
  7. Unbolt the power steering pump from the front engine cover and reposition it to one side. Do not disconnect the fluid lines.
  8. Disconnect the heater inlet pipe from the lower intake manifold and the upper radiator hose from the engine.
  9. Unfasten the lower intake manifold bolts, then lift the lower intake manifold off of the engine.
  10. Remove the lower intake manifold gasket and the RTV sealer. Thoroughly clean the gasket mating surfaces with a suitable degreaser.

 

See Figure 3

Click image to see an enlarged view

Fig. Fig. 3: Lower intake manifold

 

To install:

  1. Apply a bead of RTV sealer on each ridge where front and rear of the lower intake manifold contact the engine block. Install the lower intake manifold gaskets.



WARNING An oil leak may result if the vertical attaching bolts are not tightened before the diagonal attaching bolts.

  1. Position the lower intake manifold onto the block. Align the bolt holes. Apply sealer to the manifold bolts and install hand tight into the manifold. Tighten the vertical attaching bolts first, to 115 inch lbs. (13 Nm), then the diagonal bolts to 115 inch lbs. (13 Nm).
  2. Connect the upper radiator hose to the engine .
  3. Connect the heater inlet pipe to the lower intake manifold.
  4. Install the power steering pump to the front engine cover.
  5. Install the fuel rail
  6. Use back-up wrench to connect the fuel feed and return pipe to the fuel rail.
  7. Install the right (rear) and left (front) valve rocker cover.
  8. Install the upper intake manifold, as outlined earlier. Make sure to follow the proper torque sequence.
  9. Fill the coolant system.
  10. Connect the negative battery cable and check for leaks

 

CYLINDER HEAD:

 

3.4L Engine

LEFT SIDE

  1. Disconnect the negative battery cable.
  2. Drain and recycle the engine coolant.
  3. Remove the rocker arm covers, upper intake manifold, lower intake manifold, and exhaust manifold and crossover pipe
  4. Remove the oil level indicator assembly retaining bolt, and remove the indicator assembly.
  5. Loosen the rocker arms and remove the pushrods. Make sure to keep the pushrods in order for installation.
  6. Unfasten the cylinder head mounting bolts, then remove head from the engine. Remove and discard the gasket
  7. Thoroughly clean the gasket mounting surfaces, head bolts and cylinder block threads. Once the cylinder head has been removed, it is best to clean and check the head for straightness and cracks.

It is usually best to engage the services of a local machine shop to perform these checks.

See Figure 2

Click image to see an enlarged view

Fig. Fig. 2: Cylinder head mounting and bolt torque sequence-3.4L engine

 

To install:

  1. Place the new gasket in position over the dowel pins, with the note "This Side Up" showing.
  2. Position the cylinder head over the dowel pins.
  3. Install the cylinder head bolts. Tighten in the sequence shown in the accompanying figure to 33 ft. lbs. (45 Nm), plus an additional 90 ° rotation with the torque angle meter.
  4. The remainder of installation is the reverse of the removal procedure.
  5. Adjust valve lash according to the directions given in .
  6. Fill fluid levels, change oil and filter.
  7. Connect the negative battery cable.


RIGHT SIDE

  1. Disconnect the negative battery cable.
  2. Drain and recycle the engine coolant.
  3. Remove the rocker arm covers, upper intake manifold, lower intake manifold, and exhaust manifold and crossover pipe
  4. Loosen the rocker arms and remove the pushrods. Make sure to keep the pushrods in order for installation.
  5. Unfasten the cylinder head mounting bolts, then remove head from the engine. Remove and discard the gasket
  6. Thoroughly clean the gasket mounting surfaces, head bolts and cylinder block threads. Once the cylinder head has been removed, it is best to clean and check the head for straightness and cracks.

It is usually best to engage the services of a local machine shop to perform these checks.

To install:

  1. Place the new gasket in position over the dowel pins, with the note "This Side Up" showing.
  2. Position the cylinder head over the dowel pins.
  3. Install the cylinder head bolts. Tighten in the sequence shown in the accompanying figure to 33 ft. lbs. (45 Nm), plus an additional 90 ° rotation with the torque angle meter.
  4. The remainder of installation is the reverse of the removal procedure.
  5. Adjust valve lash according to the directions given in .
  6. Fill fluid levels, change oil and filter.
  7. Connect the negative battery cable.


Edited by eric on 5/3/2010 at 7:33 PM EST
Eric, Automotive Repair Shop Manager
Category: Pontiac
Satisfied Customers: 24301
Experience: 20+ yrs. experience as repair shop manager and technician.
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