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.
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HOMESERVICE MANUALSCHEVROLET2012EXPRESS 2500 V8-4.8LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTTUNE-UP AND ENGINE PERFORMANCE CHECKSSPARK PLUGSERVICE AND REPAIR
2012 Chevrolet Express 2500 V8-4.8L
Spark Plug: Service and Repair
2012 Chevrolet Express 2500 V8-4.8LSECTION 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 one at a time. Place each plug in a tray marked with the corresponding cylinder numbers.
Installation Procedure
1. Inspect each spark plug gap. Adjust each plug as needed.
Spark plug gap: 1.01 mm (0.040 in)
2. Hand start the spark plugs in the corresponding cylinders.
Caution:
Refer to Fastener Caution Fastener Caution.
3. Tighten the spark plugs for used heads to 15 Nm (11 lb ft). Tighten the spark plugs for new aluminum heads to 20 Nm (15 lb ft). Tighten the spark plugs for new iron heads to 30 Nm (22 lb ft).
4. Install the spark plug wires. Refer to Spark Plug Wire Replacement Service and Repair.
RENDER: 1.0x
NO RELATED
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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.