Spark plugs 4.0L (Discovery 3)

Removal

1. Disconnect the ground cable from the battery. For more information, refer to Specification.

2. Remove the engine cover. For more information, refer to Engine Cover - 4.0L (12.30.50)

3.

CAUTION: When pulling out the spark plug wire, be sure to twist the wire boot to avoid possible damage to the spark plug wire.

NOTE: Remember the position in which the part was installed.

Disconnect the high voltage (HT) electrical connectors.

4.

CAUTION: Wear eye protection.

NOTE: Use compressed air to remove all foreign material from the spark plug recesses.

Clean the area around the spark plugs.

5. Remove the spark plugs.

Installation

1.

CAUTION: Before installing new copper spark plugs, check the interelectrode gaps, they should be 1.4 mm, adjust if necessary. The gap of existing platinum or copper spark plugs must not be changed during service work; if the gap is incorrect, new spark plugs must be installed.

NOTE: Do not apply lubricant to threads.

Screw in the spark plugs.

• Check the spark plug gap (see specifications).
• Tighten the spark plugs (tightening torque 18 Nm).

2.

CAUTION: Install the spark plug wires according to the positions noted during removal.

Do not cross the wires. Connect the HT electrical connectors. Apply silicone grease to the inside of the spark plug housing.

3. Install the engine cover. For more information, refer to Engine Cover - 4.0L (12.30.50)

4. Connect the ground cable to the battery. For more information, refer to Specification.