2005 GMC C2500 w/ a 6.0L engine. Replacing your spark plugs on this engine type and similar is a very basic procedure that most individuals are capable of doing themselves. The tools needed for the job are: latex gloves, 3/8” drive in. lb. torque wrench, 3/8” drive ratchet, short and medium length 3/8” drive extensions, anti-seize compound, silicone (dielectric) electrical grease, spark plug wire puller pliers, 5/8” spark plug socket for 3/8” drive ratchet, and a set of eight factory replacement spark plugs (you can use other replacement spark plugs but certain vehicle parts I like to go back with factory equipment).
- Remove spark plug wires from spark plugs as shown in picture; label them if you don’t think you’ll remember. Remove spark plugs as shown in picture.
3. Install new spark plugs into cylinder head spark plug holes. The new spark plugs for this particular model are already pre-gapped so you will not have to measure the clearance between the electrodes. ALWAYS begin threading the new spark plugs by hand before using a ratchet or other tool as shown in picture.
4. Use the spark plug socket, 3/8” drive extension (whichever length works best for you), and 3/8” ratchet to tighten the spark plugs. Once the spark plugs begin to feel tight, swap your 3/8” drive ratchet for your 3/8” drive in. lb. torque wrench and finishing tightening the spark plugs to 12-14 ft. lbs. (144-168 in. lbs.) of torque as shown in picture.
5. Before reconnecting the spark plug wires to the spark plugs, lubricate the tips of the spark plug wires with silicone (dielectric) grease as shown in picture. I like to go ahead and remove the spark plug wires from the coil packs at the same time and place a small amount of silicone (dielectric) grease on the coil pack tips as well before reconnecting the spark plug wiress
6. Re-attach the spark plug wires. Recheck that all your spark plug wires are tight, in the correct order, and not touching anything except at their connection ends.
7. Check that you have removed all tools and other debris from under the hood. Start the engine to verify correct engine operation. Then pat yourself on the back for a job well done: congratulations, you just saved yourself 1-2 hours of mechanic labor charges as well as the “supplies” charge they add to the labor charges.