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 MANUALSCHEVROLET2008EXPRESS 2500 V8-4.8LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTTUNE-UP AND ENGINE PERFORMANCE CHECKSSPARK PLUGSERVICE AND REPAIR
2008 Chevrolet Express 2500 V8-4.8L
Spark Plug: Service and Repair
2008 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 1 at a time. Place each plug in a tray marked with the corresponding cylinder numbers.
Installation Procedure
Note: The spark plug comes pre-gapped. Do not change the spark plug gap from 1.01 mm (0.040 in).
1. Inspect each spark plug gap. Adjust each plug as needed. Refer to Ignition System Specifications Specifications.
2. Hand start the spark plugs in the corresponding cylinders.
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
3. Tighten the spark plugs.
Tighten
- For used heads tighten the spark plugs to 15 Nm (11 lb ft).
- For new aluminum heads tighten the spark plugs to 20 Nm (15 lb ft).
- For new iron heads, tighten the spark plugs to 30 Nm (22 lb ft).
4. Install the spark plug wires. Refer to Spark Plug Wire Replacement Service and Repair.
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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.