Valve Adjustment

This procedure covers inspection and adjustment of valve lash on the 2014-2018 Chevrolet Silverado 1500 with the 5.3L EcoTec3 L83 engine, which uses hydraulic roller lifters that require periodic checking and adjustment.

Warnings

Tools required

Parts

• Valve cover gasket (left bank) × 1 — GM 12643471 or equivalent
• Valve cover gasket (right bank) × 1 — GM 12643471 or equivalent
• Valve cover bolt grommets × 16 — Use OEM specification
• Ignition coil seals × 8 — Use OEM specification
• RTV silicone sealant (if needed) × 1 — GM 12378521 or equivalent

Preparation

1. Ensure engine is completely cold (at least 4 hours after last operation)
2. Disconnect negative battery cable and secure away from terminal
3. Remove engine cover by pulling upward on retention clips
4. Label and disconnect ignition coil connectors from all 8 coils
5. Remove all 8 ignition coils and set aside in order
6. Disconnect PCV hoses and any vacuum lines connected to valve covers
7. Remove wire harness retaining clips from valve covers
8. Tag or photograph any connectors and hose locations for reassembly

Procedure

1. 1

   Remove right (passenger side) valve cover
   Remove the valve cover bolts in reverse of tightening sequence (work from outside toward center). Carefully lift the valve cover off, breaking the gasket seal with a plastic scraper if necessary. Do not pry against the gasket mating surface on the cylinder head.
   Torque spec

   Cover Bolts20 Nm (15 lb-ft)
2. 2

   Remove left (driver side) valve cover
   Remove the valve cover bolts in reverse of tightening sequence. Carefully lift the valve cover off. You may need to maneuver around brake master cylinder and other components on the driver side.
   Torque spec

   Cover Bolts20 Nm (15 lb-ft)
3. 3

   Rotate engine to TDC cylinder 1
   Using a socket on the crankshaft bolt, rotate the engine clockwise (viewed from front) until the timing mark on the harmonic balancer aligns with the 0-degree mark on the timing cover. Verify cylinder 1 is at TDC compression stroke by checking that both intake and exhaust valves are closed (rocker arms loose) on cylinder 1.
   ⚠Only rotate engine in clockwise direction. Never turn backward as this can damage timing components.
4. 4

   Adjust valves on cylinder 1
   With cylinder 1 at TDC, check valve lash using feeler gauge between rocker arm and valve stem tip. Specification is 0.010 inch for both intake and exhaust. To adjust: loosen the lock nut on the rocker arm pivot stud, turn the adjustment screw until proper lash is achieved, then hold the adjustment screw stationary while tightening the lock nut. Recheck lash after tightening.
   ℹ️Ensure cam lobe is pointing away from the lifter (valve closed) before checking or adjusting lash.
   Torque spec

   Valve Lash Adjusting Screw Lock Nut20 Nm (15 lb-ft)
5. 5

   Follow firing order sequence for remaining cylinders
   The firing order is 1-8-7-2-6-5-4-3. After adjusting cylinder 1, rotate crankshaft 90 degrees clockwise to bring the next cylinder in the firing order to its compression stroke. For each cylinder in sequence: verify both valves are closed (cam lobe pointing away), check lash with feeler gauge, and adjust if needed. Continue until all 8 cylinders are complete.
   ℹ️Complete rotation cycle: Start at TDC cylinder 1, then rotate 90° for cylinder 8, another 90° for cylinder 7, and so on following the firing order.
   Torque spec

   Valve Lash Adjusting Screw Lock Nut20 Nm (15 lb-ft)
6. 6

   Inspect rocker arms and pushrods
   With all valves adjusted, visually inspect all rocker arms for wear, cracks, or damage. Check that all pushrods are straight and seat properly in their lifter cups. Check rocker arm pivot balls and sockets for excessive wear. Replace any damaged components before reassembly.
7. 7

   Clean gasket mating surfaces
   Thoroughly clean the valve cover gasket mating surfaces on both cylinder heads using a plastic scraper. Remove all old gasket material and oil residue. Clean the valve cover mating surfaces as well. Wipe surfaces with a clean, lint-free cloth. Ensure no debris falls into the engine.
   ⚠Use only plastic scrapers on aluminum surfaces. Metal tools can damage the mating surface and cause oil leaks.
8. 8

   Install new valve cover gaskets
   Position new gaskets on the valve covers, ensuring they seat properly in the cover grooves. Install new bolt grommets on all valve cover bolts. If gasket does not have integral spark plug tube seals, install new ignition coil seals in the cylinder head spark plug tubes.
9. 9

   Install left valve cover
   Carefully position the left valve cover with gasket onto the cylinder head, ensuring proper alignment. Install all valve cover bolts finger-tight first. Then torque the bolts to specification in the proper sequence: start at the center and work outward in a crisscross pattern.
   ⚠Over-tightening valve cover bolts can distort the cover and cause oil leaks. Use a torque wrench and follow the sequence.
   Torque spec

   Cover Bolts20 Nm (15 lb-ft)
10. 10

    Install right valve cover
    Carefully position the right valve cover with gasket onto the cylinder head, ensuring proper alignment. Install all valve cover bolts finger-tight first. Then torque the bolts to specification in the proper sequence: start at the center and work outward in a crisscross pattern.
    ⚠Over-tightening valve cover bolts can distort the cover and cause oil leaks. Use a torque wrench and follow the sequence.
    Torque spec

    Cover Bolts20 Nm (15 lb-ft)
11. 11

    Reinstall ignition coils and connectors
    Apply a small amount of dielectric grease to the inside of each ignition coil boot. Install all 8 ignition coils in their original positions, pressing firmly until they seat completely in the spark plug tubes. Reconnect all ignition coil electrical connectors.
12. 12

    Reconnect remaining components
    Reconnect all PCV hoses, vacuum lines, and wire harness clips to the valve covers using your reference tags or photos. Ensure all connections are secure. Reconnect the negative battery cable. Install the engine cover by pressing onto the retention clips.

Reassembly

1. Double-check that all valve cover bolts are torqued to specification in the proper sequence
2. Verify all electrical connectors are fully seated and locked
3. Ensure no tools or parts are left in the engine bay
4. Confirm PCV system and vacuum lines are properly routed and connected

Verification

• Start the engine and listen for any unusual valve train noise or ticking that would indicate improper adjustment
• Allow engine to reach normal operating temperature and verify no oil leaks from valve covers
• Rev engine to 2000-3000 RPM and listen for consistent, quiet valve train operation
• Check for any misfires or rough idle conditions that might indicate ignition coil installation issues
• After first test drive, recheck valve cover area for any signs of oil seepage

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