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.
2008 Hummer H2 V8-6.2LFACTORY OEM SERVICE PROCEDURE
Spark Plug: Service and Repair
Spark Plug Replacement
Removal Procedure
1. Remove the spark plug wires. Refer to Spark Plug Wire Replacement (Service and Repair) .
2. Loosen each spark plug 1 or 2 turns.
3. Brush or air blast away any dirt from around the spark plugs.
4. Remove the spark plugs 1 at a time. Place each plug in a tray marked with the corresponding cylinder numbers.
Installation Procedure
1. Properly position each spark plug washer.
2. Inspect each spark plug gap. Adjust each plug as needed.
Spark plug gap: 1.524 mm (0.060 in)
Notice: Refer to Fastener Notice (Fastener Notice) .
3. Hand start the spark plugs in the corresponding cylinders.
4. Tighten the spark plugs.
* For used heads tighten the spark plugs to 15 N.m (11 lb ft).
* For new aluminum heads tighten the spark plugs to 20 N.m (15 lb ft).
* For new iron heads, tighten the spark plugs to 30 N.m (22 lb ft).
5. Install the spark plug wires. 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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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