Spark Plug: Service and Repair

SPARK PLUG REPLACEMENT

REMOVAL PROCEDURE

NOTE: Observe the following service precautions:
- Allow the engine to cool before removing the spark plugs. Attempting to remove spark plugs from a hot engine can cause the spark plugs to seize. This can damage the cylinder head threads.
- Clean the spark plug recess area before removing the spark plug. Failure to do so can result in engine damage due to dirt or foreign material entering the cylinder head, or in contamination of the cylinder head threads. Contaminated threads may prevent proper seating of the new spark plug.
- Use only the spark plugs specified for use in the vehicle. Do not install spark plugs that are either hotter or colder than those specified for the vehicle. Installing spark plugs of another type can severely damage the engine.




1. Remove the spark plug wires from the spark plugs.
2. Remove the spark plugs (1) from the cylinder head.

INSTALLATION PROCEDURE




1. Gap the spark plugs to the specifications. Refer to Ignition System Specifications.

NOTE: It is important to check the gap of all new and reconditioned spark plugs before installation. Pre-set gaps may have changed during handling. Use a round wire feeler gauge to be sure of an accurate check, particularly on used plugs. Installing plugs with the wrong gap can cause poor engine performance and may even damage the engine.

2. Install the spark plugs to the cylinder head.

NOTE:
- Be sure plug threads smoothly into cylinder head and is fully seated. Use a thread chaser if necessary to clean threads in cylinder head. Cross-threading or failing to fully seat spark plug can cause overheating of plug, exhaust blow-by, or thread damage. Follow the recommended torque specifications carefully. Over or under-tightening can also cause severe damage to engine or spark plug.
- Refer to Component Fastener Tightening Notice in Service Precautions.

IMPORTANT: ONLY when the cylinder head is replaced with a NEW cylinder head, the FIRST time the spark plugs are installed, tighten the spark plugs to 20 N.m (15 lb ft). All subsequent tightening of the spark plugs, tighten to 15 N.m (11 lb ft).

Tighten
Tighten the spark plugs to 15 N.m (11 lb ft).

3. Install the spark plug wires to the spark plugs.