Spark Plug Wires

This procedure covers the removal and replacement of ignition coils on a 2014-2018 Chevrolet Silverado 1500 with the 5.3L V8 L83 engine, which uses a coil-on-plug system instead of traditional spark plug wires.

Warnings

Tools required

Parts

• Ignition coil × 8 — ACDelco D581 or equivalent

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure engine is cool to the touch
3. Disconnect negative battery cable to prevent accidental ignition system discharge
4. Gather all tools and new ignition coils before beginning

Procedure

1. 1

   Remove engine cover
   Grasp the engine cover firmly at the front and rear pull-points and lift straight up to disengage the retaining grommets. Set the cover aside in a clean area.
2. 2

   Locate and identify ignition coils
   Identify all eight ignition coils mounted directly on top of the valve covers. Four coils are on each side of the engine, positioned directly above each spark plug. Note the cylinder numbering: driver side front to rear is 1-3-5-7, passenger side front to rear is 2-4-6-8.
3. 3

   Disconnect ignition coil electrical connectors
   Press the release tab on each ignition coil electrical connector and pull the connector straight off the coil. Work methodically from one side to the other. Do not pull on the wires themselves; grip only the connector body.
   ⚠Pulling on wires instead of connectors can damage the wiring harness
4. 4

   Remove ignition coil mounting bolts
   Using a 10mm socket and extension, remove the single bolt securing each ignition coil. Each coil has one bolt located at the top center. Keep bolts organized by cylinder number if coils are being tested rather than replaced.
5. 5

   Extract ignition coils from valve cover
   Grasp each ignition coil firmly and pull straight up with steady pressure to remove it from the valve cover. The coil boot may stick to the spark plug; twist gently while pulling if resistance is felt. If a boot separates from the coil and remains in the valve cover, use needle-nose pliers to extract it.
6. 6

   Clean spark plug wells
   Use compressed air or a shop vacuum to remove any debris, dirt, or oil from the spark plug wells before installing new coils. Ensure no foreign material can fall into the cylinder when the spark plug is removed. Inspect for oil contamination in the wells, which may indicate valve cover gasket or tube seal failure.
   ⚠Debris in spark plug wells can fall into cylinders and cause engine damage
7. 7

   Prepare new ignition coils
   Apply a thin coating of dielectric grease to the inside of each new ignition coil boot (the rubber end that contacts the spark plug). This prevents moisture intrusion and ensures easy removal during future service. Do not over-apply; a light coating is sufficient.
8. 8

   Install new ignition coils
   Align each new ignition coil with its corresponding spark plug well and push down firmly until the coil boot fully seats on the spark plug. The coil should sit flush against the valve cover mounting surface. Ensure the bolt hole in the coil aligns with the threaded hole in the valve cover.
9. 9

   Install and torque ignition coil bolts
   Thread each ignition coil bolt by hand first to ensure proper alignment, then torque to specification using a torque wrench. Work systematically across the engine to avoid missing any coils.
10. 10

    Reconnect electrical connectors
    Push each electrical connector onto its corresponding ignition coil until you hear and feel a distinct click, confirming the locking tab has engaged. Gently tug on each connector to verify it is secure.
11. 11

    Reinstall engine cover
    Align the engine cover grommets with the mounting posts on the engine and press down firmly at each mounting point until all grommets are fully seated. The cover should sit evenly without gaps.
12. 12

    Reconnect battery and clear codes
    Reconnect the negative battery cable and tighten the terminal securely. If any diagnostic trouble codes were present prior to the repair, clear them using a scan tool or allow the PCM to clear them through normal drive cycles.

Reassembly

1. Ensure all eight electrical connectors are securely latched
2. Verify engine cover is properly seated on all mounting grommets
3. Confirm no tools or parts were left in the engine compartment

Verification

• Start the engine and verify smooth idle with no misfires or rough running
• Check for diagnostic trouble codes using a scan tool; there should be no ignition-related codes
• Verify the check engine light is not illuminated
• Road test the vehicle under light and moderate acceleration to confirm proper engine performance
• Inspect for any visible arcing or sparking around ignition coils during a nighttime visual inspection (engine running in dark environment)

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