How to Replace Valve Cover Gaskets on a GM 3.1Lby Cayden Conor
The GM 3.1-liter engine comes in many Chevrolet vehicles, including the 2002 Malibu. Valve cover gaskets should be replaced as soon as you notice them leaking. Since the 3.1-liter engine is available over several years and in several vehicles, the process to access the valve covers might be a bit different for each vehicle. Where you might have to remove certain wires or hoses on one, you might not have to on another -- but the actual replacement of the valve cover gaskets is the same.
Left Side (Front)
Slide the drain pan under the radiator petcock. Loosen the petcock and allow the coolant to drain. If the coolant is clean and less then five years old, you can reuse it. Disconnect the negative battery cable, using the appropriate wrench. Set the cable aside, ensuring that it doesn't touch metal.
Mark any wires and vacuum hoses that are in the way of removing the valve covers, using the tape and marker. Depending on which vehicle the 3.1-liter engine is in this could vary. Remove the front ignition wire harness at the upper intake manifold and at the spark plugs by releasing it from its bracket. Depending on which vehicle you are working on, you may have to unplug the harness from some sensors to move it far enough out of the way. Ensure that you label anything you unplug.
Remove the thermostat bypass pipe, using the appropriate socket. Disconnect the PCV vacuum hose from the PCV valve and lay it aside. Unbolt the valve cover retaining bolts, using the appropriate socket. Lift the valve cover off the engine. If the valve cover won't come off easily, tap it with a rubber mallet.
Clean the gasket-mating surfaces on the valve cover and head, using the plastic scraper and rags.
Apply a thin layer of RTV silicone to the valve cover's gasket-mounting surface. Fit the gasket onto the valve cover. Fill the notch on the valve cover with RTV silicone. Allow it to set for two minutes. Install the valve cover and tighten the bolts to 89 inch-pounds of torque.
Reconnect the PCV valve vacuum line. Reinstall the thermostat bypass pipe. Reposition the front ignition wire harness and plug in any wiring harness connectors and vacuum lines that you might have removed.
Right Side (Rear)
Unplug the wiring harness connector on the alternator. Remove the power wire, using the appropriate wrench. Run the nut back onto the stud so you don't lose it. Slide a socket onto the bolt in the center of the tensioner pulley. Rotate the pulley toward the engine. Lift the serpentine belt off the alternator, but do not remove it from the rest of the pulleys. If your 3.1-liter has the V-belt system, loosen the adjusting bolt on the slider bracket. Slide the alternator toward the engine. Lift the V-belt off the alternator, but leave it on the rest of the pulleys.
Unbolt and remove the alternator, using the appropriate socket. Remove the ignition coil bracket and coils, using the appropriate socket. Set it aside -- you may be able to do this without removing any of the wires, depending on its exact location in your car. If not, be sure to label all the wires on the coils before removing the wires to access the bracket bolts.
Remove the vacuum hose from the grommet in the right valve cover. Remove the accessory drive belt tensioner, if equipped, using the appropriate socket. Remove the valve cover retaining bolts then lift the valve cover off the head. If it doesn't lift right off, tap it with the rubber mallet. Clean the gasket-mating surface of the valve cover and the head, using the rubber scraper and rags.
Apply a thin layer of RTV silicone to the valve cover gasket-mating surface. Press the valve cover gasket onto the gasket-mounting surface. Allow it to set for two minutes. Install the valve cover and tighten the retaining bolts to 89 inch-pounds of torque.
Reinstall the vacuum hose at the gromment. Reinstall the ignition coils and the bracket. Reinstall the alternator and tighten the bolts firmly. Plug in the alternator and reattach the power wire. Reinstall the tensioner and the accessory drive belt. The tensioner will automatically tension the belt. If you have V-belts, route the belt over the alternator pulley, then pull the alternator away from the engine. Tighten the adjusting bolt. The belt has the proper tension when you can twist it 90 degrees.
Tighten the radiator petcock. Refill the radiator. Reattach the battery cable.