SPARK PLUG CHECK AND CLEANING

Required Special Tool

MB992273: Spark Plug Brush

caution

Never attempt to adjust the gap of the iridium plug.
Do not attempt to clean the iridium plug using a wire brush because it may result in damage to the electrode. When the iridium plug is cleaned, special tool spark plug brush (MB992273).

note	Obey the maintenance interval of the relevant vehicle for the spark plug replacement. If the plug gap and insulation resistance are normal, check the plug condition and clean if necessary.

For removal and installation procedure of the spark plug, (refer to IGNITION COIL REMOVAL AND INSTALLATION

SPARK PLUG GAP CHECK

Check the plug gap with the wire type plug gap gauge. Replace it if the limit is exceeded.

Standard value, limit:

Manufacturer	Type	Standard value mm (inch)	Limit mm (inch)
NGK	SILMAR6G8GS	0.7 – 0.8 (0.027 – 0.031)	1.0 (0.04)

SPARK PLUG INSULATION RESISTANCE CHECK

1. Measure the insulation resistance of the spark plug. If the insulation resistance of the spark plug is under the limited value, clean the spark plug.

Limit: Minimum 10 MΩ

2. After cleaning, measure the insulation resistance again. Replace the plug unless it is within the limited value.

SPARK PLUG CLEANING

1. Sufficiently apply the brake cleaner to the plug end.

note	Repeatedly applying the brake cleaner is acceptable during the cleaning.

2. Using special tool spark plug brush (MB992273), intensively clean the electrode for 1 to 2 minutes.

note	Even if using strong force, the electrode is not damaged. In case of insufficient cleaning, it is permissible to take longer than 2 minutes for cleaning.

3. After the cleaning, sufficiently remove and then dry both of the carbon and the brake cleaner on the plug, using a waste cloth or air blowing.