Annually or every 20,000 km.
Tools needed to replace spark plugs.
1 — Spark plug wrench head - equipped with a special soft insert to protect the porcelain insulator of the spark plug
2 — Torque wrench - although it is not an absolutely necessary tool, it provides the maximum guarantee of the correct tightening force of the spark plugs
3 — Ratchet drive - comes standard with the spark plug wrench
4 — Extension - depending on the car model and its accessories, you may need special extensions and universal joints to provide access to the spark plugs
5 — Spark plug gap gauge - this device for checking the spark plug gap is available in various modifications. Make sure that you have a gauge specifically for the gap of your car. You can use the blades of a feeler gauge instead
Before you begin, gather all the necessary tools, which include a replacement spark plug wrench head and a set of feeler gauge blades. Some spark plug manufacturers supply special tools for measuring the spark plug gap.
The best way to replace spark plugs is to first purchase new plugs, adjust their gap, and replace each plug one at a time. When purchasing spark plugs, it is very important to choose the correct spark plugs for your vehicle's engine. Information about these can be found in Table of sizes and adjustment data at the end of the Guide.
1. With new spark plugs on hand, allow the engine to cool completely before removing the old ones. During this time, you can inspect the new spark plugs for defects and check the spark plug gaps.
2. The spark plug gap is checked by inserting a gauge of the required thickness between the electrodes at the end of the spark plug. The gap should correspond to that specified in Table of sizes and adjustment data at the end of the Manual. The wire should just touch each of the electrodes. If the gap is not correct, slightly bend the curved part of the electrode using the knurled adjuster until the desired gap is achieved.
When adjusting the gap of a new spark plug, bend only the base of the ground electrode, not the end. If the ground electrode is offset from the center electrode, use a notched adjuster to align them. Check the porcelain insulator for cracks, indicating that the spark plug should be replaced.
3. With the engine cool, disconnect the high-voltage wire from one of the spark plugs. Do not pull the wire itself, but hold the connector at its end. Sometimes you need to use a twisting motion to disconnect the connector.
4. If possible, use compressed air to blow out dirt and debris from around the spark plugs. You can use a regular bicycle pump for this. This is done to avoid the possibility of debris getting into the cylinder after the spark plugs are removed.
5. Place the spark plug wrench head on the spark plug and remove the spark plug from the engine by turning it counterclockwise.
6. Compare the removed spark plug with those shown in the pictures, this will give you useful information about the general condition of the engine.
7. Apply a small amount of copper anti-seize compound to the threads of the new spark plug. Insert the spark plug into the cylinder head and screw it in with your fingers until it stops, then tighten it with the socket of a spark plug wrench. If possible, use a torque wrench to tighten the spark plug to ensure that it is installed correctly. The tightening torque for the spark plugs is included in Table of sizes and adjustment data at the end of the Guide.
To avoid the possibility of screwing the spark plug in incorrectly, place a small piece of rubber hose or plastic tube on its tailpiece. The flexible tube will act as a universal joint, ensuring alignment of the spark plug with the spark plug socket, and if the spark plug starts to warp, the hose will slide on it, preventing the thread from being stripped.
8. Before connecting the high-voltage (HV) wire to the spark plug, carefully inspect it as described in Section Checking and replacing spark plug wires, cover and distributor rotor.
9. Connect the wire to the installed new spark plug, again using a twisting motion and holding the connector until it is fully seated on the spark plug.
10. Repeat the above procedure for the remaining spark plugs in sequence to avoid incorrect connection of the spark plug wires.