How to Change Intake Manifold Gaskets on GM 3.4 Litres

Written by matt wooddy
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General Motors has been manufacturing a 60-degree V6 motor for its vehicles since 1980. Featuring an array of displacements and performance specifications, the 3.4L had three different variants itself. The LA1 3.4L was a bored-out version of the 3.1L, common in vehicles such as the Chevrolet Camaro and Pontiac Grand Am. Regardless of which version of the 3.4L V6 is in your automobile, changing the intake manifold gaskets on the engine block will prevent leaks and improve performance. This procedure can be done on a flat surface with the right tools and know-how.

Skill level:
Moderately Challenging

Things you need

  • Intake manifold gaskets
  • Gasket sealant
  • Engine degreaser
  • Plastic scraper
  • Wrench set
  • Torque wrench
  • Pliers
  • Empty container
  • Label stickers and pen

Show MoreHide



  1. 1

    Open the panel door, located underneath the steering column, and pull out the fuel pump relay with your hand. Start the engine and let it run until the lack of fuel causes it to shut off. Open the bonnet of your car and unscrew the bolt that holds the negative connection to the battery in place. Move this connector away from the battery so that it does not interfere with the rest of this servicing.

  2. 2

    Place an empty container under the drainage plug of your engine's radiator. Remove the filler cap at the top to allow the engine coolant to flow more easily. Open the drain one full turn with your hand and let all of the coolant drain into the empty container. Turn the drain clockwise one turn to close when you are finished. Pull on the radiator hose from its connector with a pair of pliers. Slowly remove it.

  3. 3

    Unscrew the bolts that hold the engine cover on the intake plenum. Disconnect all of the sensors and electrical wiring that attach to the intake manifold. Unfasten the air filter housing unit and open to access the air filter inside. Remove the filter from and unscrew the bolts that hold the housing unit together. Remove this tube from the throttle body.

  4. 4

    Label each spark plug wire and pull on the boot to remove from each plug. Disconnect the serpentine belt. Unscrew the wires from behind the alternator and disassemble the alternator completely. Remove the six injector plugs and their respective connectors to the 3.4L's throttle body. Pull all of the vacuum lines from the throttle body and manifold with a pair of pliers. Unscrew the nuts that hold the fuel lines to their respective fuel rails and pull up to remove them.

  5. 5

    Unscrew the bolts that hold the bracket of the throttle body to the engine. Carefully pry the bracket back with your hand to access the remaining screws that hold the throttle body into place. Unscrew these and remove the throttle body.

  6. 6

    Unscrew the bolts that hold the upper intake manifold to the engine. Lift the manifold off and set it aside for later use. Pry the upper manifold gasket from the cylinder flanges with a flathead screwdriver. Now, unscrew the bolts that hold the lower intake manifold and remove them. Pry the lower gasket with a flathead screwdriver, as well.

  7. 7

    Scrape any harsh build-up and grime that may have formed on the engine block over the years. Apply engine degreaser with a linen cloth to wipe away any remaining debris.


  1. 1

    Apply gasket sealant to both sides of the new lower intake gasket. Position this gasket on top of the engine block so that all of the holes align.

  2. 2

    Align the lower intake manifold on top of the newly installed manifold gasket. Apply 18 foot-pounds of pressure to these bolts with a torque wrench to secure. Tighten the bolts a bit at a time so that the stress of the manifold is distributed evenly.

  3. 3

    Apply gasket sealant to both sides of the new upper intake manifold gasket. Position this gasket so that it lines up perfectly with all of the holes of the engine block.

  4. 4

    Align the upper intake manifold with the newly installed upper gasket. Bolt the screws with the same 18 foot-pounds of pressure used on the lower manifold.

  5. 5

    Reconnect all of the parts that were removed or disconnected in order to remove and install new manifold gaskets. Replace the fuel pump relay and connect the negative connection to the battery to complete this procedure.

Tips and warnings

  • Wear gloves at all times to minimise your risk of injury during removal and installation

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