Q&A for How to Change an Ignition Coil

The most common spark plug size is 5/8" or 16mm. Next would be 9/16" and 14mm. Less common sizes would be 7/8", 13/16", 3/4" and 18mm.

If working on a vehicle with all coils easily exposed, you should not have to use any special tools. If working on a vehicle with a transverse-mounted V-engine, removing some additional components may be necessary. Some new vehicles may have a hex bolt or star bolt holding the coils in place. It is always a good idea to inspect your vehicle before starting any procedures.

There is a sequence for the coils and leads. Follow each lead back to the source. It will typically have the number of the corresponding cylinder it goes to.

You need to remove the connector from the coil pack before removing the pack from the vehicle. Disconnecting the negative battery cable prevents any short circuit if the power terminal comes into contact with a ground source.

Not disconnecting the battery can potentially damage the ignition coil, but it doesn't always lead to it burning out. The risk arises because working on the ignition system or electrical components with the battery connected can cause electrical surges or short circuits that may overheat or damage the ignition coil. Disconnecting the battery before working on the vehicle helps prevent these risks and protects the ignition system.