To change spark plugs, follow these steps:
- Preparation: Locate the spark plugs under the bonnet using your vehicle manual. Clean the area around the plugs and make sure the engine is cool.
- Remove Ignition Lead: Remove one ignition lead (thick wire) at a time from each spark plug to avoid confusion.
- Remove Old Spark Plug: Use a spark plug socket with a ratchet or spanner to unscrew and remove the old spark plug.
- Prepare New Spark Plug: Check and adjust the electrode gap on the new plugs using a gap gauge according to your vehicle's specs. Apply a small amount of copper or anti-seize grease on the threads if recommended.
- Install New Spark Plug: Thread the new plug into the hole by hand to avoid cross-threading. Tighten it using a torque wrench to the specified torque in the manual, usually an eighth to a quarter turn after snug.
- Reattach Ignition Lead: Snap the ignition lead back onto the plug secure connection.
- Repeat for All Plugs: Repeat the process one by one for all spark plugs.
- Final Checks: Clean up and replace any parts you removed to access the plugs.
Some tips:
- Work on a cold engine to avoid burns or damage.
- Using a torque wrench ensures proper tightening without risk of damage.
- If you don’t have a torque wrench, snug and turn 1/4 turn more is often acceptable.
- Replace ignition leads if damaged.
- Never over-tighten the spark plugs.
- Clean the spark plug hole before installing new plugs if dirt is present.
This process can be done at home with basic tools: spark plug socket, ratchet, torque wrench, and gap gauge.
