Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2009 Hummer H3 V8-5.3LFACTORY OEM SERVICE PROCEDURE
Spark Plug: Service and Repair
Spark Plug Replacement
Removal Procedure
1. Remove the spark plug wire. Refer to Spark Plug Wire Replacement (Service and Repair).
2. Loosen the spark plug 1-2 turns.
3. Brush or using compressed air, blow away any dirt from around the spark plug.
4. Remove the spark plug.
If removing more than one plug, place each plug in a tray marked with the corresponding cylinder number.
Installation Procedure
1. Correctly position the spark plug washer.
2. Inspect the spark plug gap. Adjust the gap as needed. Refer to Ignition System Specifications (Specifications).
3. Hand start the spark plug in the corresponding cylinder.
Caution: Refer to Fastener Caution (Fastener Caution).
4. Tighten the spark plug.
Tighten the plug to 20 Nm (15 lb ft).
5. Install the spark plug wire. Refer to Spark Plug Wire Replacement (Service and Repair).
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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