Spark Plug Damages - Possible Causes and Failure Modes Opel Agila B

Field Remedy: 1826

Remedy:

Most frequent failures

Failure mode: - thermal overload at centre-, ground electrode, insulator foot - broken centre-, ground electrode - insulator foot broken - thread damaged, wrenched

Fault causes: - tightening torque too low - tightening torque too high

1. Thermal overload (Picture I)

Tightening torque too low (< 15 Nm) - spark plug was not correct tightened thereby the heat transfer was disturbed - centre-, ground electrode and insulator foot are melted

2. Broken centre electrodes (Picture II)

Tightening torque too low (< 15 Nm) - outer sealing ring thickness > 1,4 mm - vibration marks at the terminal head

Through vibrations the spark plug loosened and the centre electrode broke.

3. Broken centre- and ground electrode (Picture III)

Tightening torque too low (< 15 Nm) - thickness of outer sealing ring > 1,4 mm

The spark plugs loosened caused by vibrations. Hence it follows breaking of ground- and centre electrode and break out of the insulator foot.

4. Insulator foot fracture (Picture IV)

Tightening torque too high (> 35 Nm) - outer sealing ring thickness < 1,2 mm

Compound housing/insulator loosened

Spark plug got untight

Through shaking of the plug the spark plug has been completely destructed.

5. Thread wrenched

Tightening torque too high (> 50 Nm) - strong tracks of the spark plug -wrench at the hexagon - forced rupture in the thread

Subsequent damage (e.g. engine, cylinder) caused by described failures must not be covered by warranty.