How to Replace Valve Cover Gaskets on Chevrolet Cars

by Contributing Writer; Updated June 12, 2017

The valve cover gasket on the Chevrolet car is designed to prevent oil from leaking from the sides of the valve cover. The motor oil is pumped up out of the oil pan and into the crankcase. The oil then reaches the valves and the rocker arms. If the valve cover gasket has any cracks or damaged areas, the motor oil will leak out of the valve cover and get all over the engine. Once the valve cover begins to leak oil, it will have to be replaced.

Under The Hood:

 How to Replace Valve Cover Gaskets on a GM 3.1L

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.

Items you will need

  • Drain pan

  • Set of wrenches

  • Tape and marker

  • Set of sockets

  • Rubber mallet

  • Plastic scraper

  • Rags

  • RTV silicone

  • Torque wrench

 How to Change a Valve Cover Gasket on a 2.2L Chevrolet S10

Removal

Open the hood. Allow the engine to cool completely.

Loosen the clamps holding the air cleaner duct assembly to the intake hose with a screwdriver. Separate the duct and lift it out of the engine compartment.

Grasp the throttle cable at the cable support bracket located near the throttle. Pull up on the cable to unsnap it from the bracket.

Pull the brake booster hose off its nipple on the top of the rocker cover. Pull the positive crankcase ventilation valve from the front, inside edge of the rocker box.

Remove the rocker cover bolts with a ratchet and socket. Lift the rocker cover off the engine. Remove the old gasket from the engine and cover with a gasket scraper.

Wipe any sludge or residue from the rocker cover and its mating surface on the engine with a shop rag. Inspect the flange on the rocker cover for distortion or damage. Replace it if necessary.

Installation

Place the new gasket into the groove in the top of the engine. Position the rocker cover on top of the engine and start the bolts by hand.

Tighten the rocker cover bolts using a cross pattern. Torque the rocker cover bolts to 89 inch-pounds with a 1/4-inch torque wrench and a socket.

Insert the PCV valve into the rocker cover. Install the brake booster hose onto its nipple. Snap the throttle cable into the support bracket by hand.

Position the air duct in the engine compartment. Slide the air hose onto the duct and tighten the clamp with a screwdriver.

Items you will need

  • Screwdriver

  • Ratchet

  • Socket set

  • Gasket scraper

  • Shop rag

  • New rocker cover gasket

  • Torque wrench

 How to Change the Valve Cover Gasket on a Chevrolet Silverado

Park the Chevy Silverado on level ground and open the hood. Locate both valve covers on the top of the engine. If the engine is warm or hot, allow it to cool before proceeding.

Remove the bolts that secure the valve covers to the engine using the ratchet set. Pull the valve covers off the top of the engine. Locate the valve cover gaskets on the edge that connects to the engine.

Scrape the gaskets off of both valve covers using the thin metal scraper. Ensure that only the metal surface of the cover's edge is visible so that you know all of the old gasket is completely removed.

Peel the paper cover on the edge of one of the new valve cover gaskets. Place the new gasket on the edge of one of the cover that connects to the top of the engine. Make sure that the gasket does not overlap with the edge of the cover on either side. Repeat for the other cover.

Replace both valve covers to the engine and replace the securing bolts to the covers. Tighten the Silverado's valve cover securing bolts to the torque specifications for that specific truck using the torque wrench.

Items you will need

  • Ratchet set

  • Thin metal scraper

  • 2 new valve cover gaskets

  • Torque wrench

 How to Replace the Valve Cover Gasket on a Chevrolet Trailblazer

Park the Chevrolet Trailblazer in a safe area and open the hood.

Locate the valve cover that has the leaking valve cover gasket.

Remove all of the bolts that are connecting the valve cover to the top of the engine block with the 3/8-inch drive ratchet and a socket. Turn the bolts counterclockwise to loosen and remove.

Carefully pull the valve cover off the engine block. Remove the old gasket from the bottom of the valve cover.

Wipe the gasket area on the valve cover well with a clean rag. Then, wipe the surface of the engine block where the valve cover gasket seats with a clean rag as well.

Position the new valve cover gasket onto the bottom of the valve cover in the correct position. The valve cover gasket is made to fit one way on the bottom of the valve cover. Put the gasket onto the valve cover in the same direction in which the old valve cover gasket was. Make sure that the new gasket is properly seated.

Put the valve cover back over the top of the engine block. Match up the bolt holes and screw the bolts into the valve cover hand tight.

Tighten the bolts down in a sequence so that the new valve cover gasket will pull down evenly. Tighten one bolt on each side at a time. Then, tighten one bolt on each end of the valve cover at a time. Keep rotating the tightening sequence until the bolts are completely tight.

Crank the engine and let it run for two or three minutes. Inspect the new valve cover gasket for leaks while the engine is running. Then, turn the engine off and close the hood.

Items you will need

  • 3/8-inch drive ratchet

  • 3/8-inch drive extension

  • 3/8-inch drive sockets

  • Clean rags

  • New valve cover gasket

 How to Replace the Valve Cover Gasket on a 350

Remove the two bolts that secure the top of the valve cover to the cylinder head with a wrench, followed by the two bolts at the bottom of the valve cover.

Insert the blade of a flathead screwdriver between one side of the valve cover and the cylinder head, then twist the blade to unseal the valve cover from the cylinder head.

Turn the valve cover upside down to expose the gasket, then pull the gasket off the cover.

Apply a single bead of gasket sealant around the lip of the valve cover, then position the replacement gasket onto the sealant.

Position the gasket on the valve cover so that each of the gasket's four bolt holes aligns with the bolt holes on the edges of the valve cover.

Apply a single bead of gasket sealant to the valve cover gasket, then place the valve cover on the cylinder head.

Install and tighten each of the valve cover's four bolts with a wrench.

Items you will need

  • Wrench

  • Flathead screwdriver

  • Gasket sealant

  • Replacement gasket

 How to Replace the Valve Cover Gasket in a Geo Tracker

Allow your engine to cool. Disconnect the negative battery cable. Remove the air inlet hose and air intake case or air cleaner housing. Detach the PCV valve hose from the PCV valve. Separate and remove the spark plug wires and the accelerator cable from their clips.

Loosen and remove the valve cover bolts. Lift the cover up and off. Using a flathead screwdriver, gently nudge the gasket out of the gasket seating area. Using automotive engine cleaner and a clean cloth rag, clean the gasket seating area.

Place the new gasket in the gasket seating area. Put the cover back into place. Put the bolts in and then using a torque wrench tighten them. Do not over tighten the bolts or the gasket will not fit correctly. Reconnect the spark plug wires and the accelerator cable in the holding clips.

Reconnect the rubber hose to the PCV valve. Install the air intake case, or air cleaner housing, and the air inlet hose. Reconnect the negative battery cable. Add oil to the car and start the engine. Allow the car to run 10 to 15 minutes. This will allow the oil to lubricate the engine while it moves to the top.

Items you will need

  • Flathead screwdriver

  • Torque wrench

  • Automotive engine cleaner

  • Clean cloth rag

  • Valve cover gasket

  • Valve cover gasket kit

  • 1 to 2 quarts of motor oil