Parts and equipment specialist and leading spark plug supplier, Bosch, has issued some useful information on the importance of using the right tools to change spark plugs. Use of the wrong tools can cause unnecessary job delays and can often cause plug damage. 

Bosch stress that changing spark plugs is a critical maintenance task that requires the proper tools to ensure efficiency and recommends utilising a rubberised or magnetic spark plug socket, along with the correct-sized extension. 

Use of a rubberised or magnetic spark plug socket and extension in the correct size also prevents the spark plug from falling out or, sliding too deeply into the tool. The rubber or magnetic insert also provides necessary space between the spark plug and the tool. This prevents lateral forces on the spark plug and the space behind the spark plug prevents it from being pushed out by the attached tool. 

When using spark plugs with solid washer, the recommended torque is achieved significantly faster than with spark plugs that have a crushable washer. After hand-tightening, only a very small rotation angle may be needed to reach the required torque.

Bosch recommends mounting the spark plug by hand as far as it will go, then precisely tightening using the correct tightening torque. 

A useful video on best practice spark plug fitting can viewed on the Bosch Aftermarket YouTube Channel below.