engine

Valve Cover Gaskets - Both

for 2011 Chevrolet Avalanche 5.3L Vortec V8 (flex-fuel, Active Fuel Management) · 4WD

🔓 Unlocked for everyone by Simon-Olivier Ricci · 2026-08-23

Difficulty

Moderate

Time

2.6 h

Tools

Steps

✓Fact-checked. Built from OLP's spec database, then independently fact-checked line by line with every correction applied. Master-tech sign-off by Chris Hackleman is queued. Cross-check torque values against the factory manual, and stop if anything looks unsafe. How our data is made.

This procedure removes and replaces both valve cover gaskets on the 5.3L Vortec V8 engine, requiring removal of ignition coils, wiring harnesses, and associated components to access the valve covers.

Warnings

⚠Allow engine to cool completely before beginning work. Hot engine components can cause severe burns.

⚠Do not over-torque valve cover bolts. The covers are aluminum and bolts thread into aluminum cylinder heads, which can strip easily.

ℹ️This engine uses Active Fuel Management (AFM). Some valve cover bolt locations may have oil passage seals that must be replaced with new grommets.

Tools required

Socket set (8mm, 10mm, 13mm)Essential

Torque wrench (5-100 Nm range)Essential

Ratchet and extensions (6-inch and 12-inch)Essential

Flathead screwdriver or trim tool

Wire brush or gasket scraper (plastic recommended)Essential

Brake cleaner or degreaserEssential

Shop rags or paper towelsEssential

Needle-nose pliers

Magnetic pick-up tool

Engine oil drain pan

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Parts

Driver-side valve cover gasket × 1 — GM 12612350 or equivalent
Passenger-side valve cover gasket × 1 — GM 12612350 or equivalent
Valve cover bolt grommets (set of 18) × 1 — GM 12476637 or equivalent
PCV valve grommet × 1 — Use OEM specification

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Preparation

Park vehicle on level surface and engage parking brake
Allow engine to cool completely (at least 2 hours after running)
Disconnect negative battery cable
Remove engine cover by lifting upward from front edge (press-fit clips)
Take photos of wiring harness routing for reference during reassembly

Procedure

1
Remove driver-side ignition coils and wiring
Disconnect the electrical connectors from all 4 driver-side ignition coils by pressing the release tab and pulling straight up. Remove the single 10mm bolt securing each coil. Pull each coil straight up off its mounting stud on the valve cover coil bracket after removing the bolt. Set coils aside in order from front to back.
2
Disconnect driver-side valve cover wiring and hoses
Disconnect the wire harness connectors from the fuel injectors (4 connectors). Unclip the wire harness from the valve cover and carefully move it aside. Disconnect the PCV hose from the valve cover by pulling firmly. Disconnect the evaporative emission (EVAP) purge line from the rear of the driver-side valve cover if equipped.
ℹ️Note the routing of all harnesses and hoses for proper reinstallation.
3
Remove driver-side valve cover
Remove the 4 valve cover bolts in a criss-cross pattern using an 8mm socket. Carefully lift the valve cover straight up. If stuck, gently tap with a rubber mallet or carefully pry at the designated pry points (cast tabs on the cover). Do not pry between the cover and cylinder head gasket surface. Inspect the bolt grommets and replace any that are damaged or deteriorated.
⚠Do not damage the aluminum gasket sealing surface on the cylinder head or valve cover.
4
Clean driver-side gasket surfaces
Remove all old gasket material from both the valve cover and cylinder head using a plastic scraper or wire brush. Clean surfaces thoroughly with brake cleaner and wipe dry with clean rags. Inspect the cylinder head surface for warping or damage. Ensure all bolt hole areas are clean and free of oil or debris.
⚠Do not use metal scrapers that could gouge the aluminum sealing surfaces.
5
Remove passenger-side ignition coils and wiring
Disconnect the electrical connectors from all 4 passenger-side ignition coils. Remove the single 10mm bolt securing each coil. Pull each coil straight up from the spark plug tube with a twisting motion. Set coils aside in order from front to back.
6
Disconnect passenger-side valve cover wiring and components
Disconnect the wire harness connectors from the fuel injectors (4 connectors). Unclip the wire harness from the valve cover and move it aside. If equipped with an oil fill tube mounted to the passenger-side valve cover, remove the mounting bolt and pull the tube from the cover grommet. Disconnect any breather hoses from the valve cover.
ℹ️The passenger side typically has the oil fill tube integrated into or mounted to the valve cover.
7
Remove passenger-side valve cover
Remove the 4 valve cover bolts in a criss-cross pattern using an 8mm socket. Carefully lift the valve cover straight up. If stuck, gently tap with a rubber mallet or carefully pry at the designated pry points. Do not pry between the cover and cylinder head gasket surface. Inspect the bolt grommets and replace any that are damaged.
⚠Do not damage the aluminum gasket sealing surface on the cylinder head or valve cover.
8
Clean passenger-side gasket surfaces
Remove all old gasket material from both the valve cover and cylinder head using a plastic scraper. Clean surfaces thoroughly with brake cleaner and wipe dry with clean rags. Inspect the cylinder head surface for warping or damage. Ensure all bolt hole areas are clean and free of oil or debris.
⚠Do not use metal scrapers that could gouge the aluminum sealing surfaces.
9
Install new driver-side valve cover gasket
Install new bolt grommets into all 4 bolt holes in the driver-side valve cover. Position the new gasket onto the valve cover, ensuring it seats properly in the groove around the perimeter. The gasket should fit snugly without stretching or compression. Install new PCV valve grommet if replacing.
ℹ️Some technicians prefer to install the gasket onto the cylinder head instead of the cover. Either method works if the gasket stays in position during installation.
10
Install driver-side valve cover
Carefully lower the valve cover with gasket onto the cylinder head, ensuring the gasket remains properly positioned. Start all 4 bolts by hand to prevent cross-threading. Tighten the bolts in a criss-cross pattern from the center outward to the specified torque of 12 Nm (106 lb-in). Do not over-torque.
⚠Over-torquing valve cover bolts can crack the valve cover or strip threads in the aluminum cylinder head.
11
Reconnect driver-side wiring and hoses
Reconnect the PCV hose to the valve cover. Reconnect the EVAP purge line if equipped. Route the fuel injector wire harness back into position and clip it to the valve cover retainers. Reconnect all 4 fuel injector electrical connectors, ensuring they click into place.
ℹ️Refer to photos taken during disassembly to ensure correct harness routing.
12
Reinstall driver-side ignition coils
Apply a small amount of dielectric grease to the inside of each ignition coil boot. Install each coil onto its mounting location on the valve cover coil bracket in the correct order (front to back as removed). Install the 10mm mounting bolt for each coil and torque to 8 Nm (6 lb-ft). Reconnect the electrical connector to each coil.
13
Install new passenger-side valve cover gasket
Install new bolt grommets into all 4 bolt holes in the passenger-side valve cover. Position the new gasket onto the valve cover, ensuring it seats properly in the groove. If the oil fill tube was removed, install a new grommet into the valve cover before reinstalling the tube.
14
Install passenger-side valve cover
Carefully lower the valve cover with gasket onto the cylinder head, ensuring the gasket remains properly positioned. If the oil fill tube mounts to the cover, ensure it is properly seated in the grommet. Start all 4 bolts by hand. Tighten the bolts in a criss-cross pattern from the center outward to the specified torque of 12 Nm (106 lb-in).
⚠Over-torquing valve cover bolts can crack the valve cover or strip threads in the aluminum cylinder head.
15
Reconnect passenger-side wiring and components
If the oil fill tube was removed, secure it with its mounting bolt. Route the fuel injector wire harness back into position and clip it to the valve cover retainers. Reconnect all 4 fuel injector electrical connectors. Reconnect any breather hoses to the valve cover.
16
Reinstall passenger-side ignition coils
Apply a small amount of dielectric grease to the inside of each ignition coil boot. Install each coil into its spark plug tube in the correct order, pushing down firmly until seated. Install the 10mm mounting bolt for each coil and torque to 8 Nm (6 lb-ft). Reconnect the electrical connector to each coil.
17
Final reconnection and inspection
Reconnect the negative battery cable. Reinstall the engine cover by aligning the clips and pressing down firmly until it clicks into place. Inspect all connections to ensure nothing was missed. Check that all electrical connectors are fully seated and locked.

Reassembly

Torque all fasteners to specification using a criss-cross pattern for valve cover bolts
Ensure all electrical connectors are fully seated and locked before starting engine
Double-check that all hoses (PCV, EVAP, breather) are properly connected

Verification

Start the engine and allow it to idle for 2-3 minutes while observing both valve covers for oil leaks
Check around all valve cover bolt locations and gasket perimeters for any sign of oil seepage
Rev engine to 2000-2500 RPM briefly and recheck for leaks
Verify no error codes are present and engine runs smoothly with all cylinders firing
After engine reaches operating temperature, shut off and allow to cool, then recheck valve cover bolt torque after first heat cycle if desired

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