Ignition system (Discovery 3)

1. Every 12 months or 24,000 km - vehicles with engines running on LEADED fuel or vehicles equipped with COPPER spark plugs: Replace the spark plugs.
For more information, please refer to Specifications (303-07 Engine Ignition - 4.0L)
For more information, please refer to Specifications (303-07 Engine Ignition - 4.4L)
For more information, please visit Spark Plugs (303-07 Engine Ignition - 4.0L)
For more information, please visit Spark Plugs (303-07 Engine Ignition - 4.4L)

2. Every 3 years or 72,000 km - vehicles operated under severe conditions: Replace spark plugs.
For more information, please refer to Specifications (303-07 Engine Ignition - 4.0L)
For more information, please refer to Specifications (303-07 Engine Ignition - 4.4L)
For more information, please visit Spark Plugs (303-07 Engine Ignition - 4.0L)
For more information, please visit Spark Plugs (303-07 Engine Ignition - 4.4L)

3. Every 6 years or 90,000 miles (144,000 km) - 4.0L V6 and 4.4L V8 engines - North American vehicles: Replace spark plugs.
For more information, please refer to Specifications (303-07 Engine Ignition - 4.0L)
For more information, please refer to Specifications (303-07 Engine Ignition - 4.4L)
For more information, please visit Spark Plugs (303-07 Engine Ignition - 4.0L)
For more information, please visit Spark Plugs (303-07 Engine Ignition - 4.4L)

4. Every 6 years or 90,000 miles (144,000 km) - 4.0L V6 engines - All other markets vehicles that use UNLEADED fuel but are not driven under severe conditions: Replace the spark plugs.

For more information, please refer to Specifications (303-07 Engine Ignition - 4.0L)
For more information, please visit Spark Plugs (303-07 Engine Ignition - 4.0L)

5. Every 7 years or 108,000 miles (168,000 km) - 4.4L V8 engines - except North American vehicles: Replace spark plugs.
For more information, please refer to Specifications (303-07 Engine Ignition - 4.4L)
For more information, please visit Spark Plugs (303-07 Engine Ignition - 4.4L)