Hi, this is my first post so Hello to all.
My 2001 Astra 2.2 Coupe, 70K and regularly serviced, recently suffered from a loud rattling noise and misfire whilst driving on the motorway. I pulled over and called the AA who removed the coil pack and diagnosed a loose spark plug in no 4 cylinder. Closer inspection showed that the threads engine side had been stripped. AA recommended that the hole can be retapped then have a helicoil fitted and can be done in situ without stripping the engine. I'm calling in a professional for this.
My concern is that the plug looks almost as if it has been hit from underneath and I am worried that if I have the threads repaired and then start the engine then the new plug will also be hit by whatever caused the problem in the first place.
Has anyone ever heard of this happening before?
Is it possible for something to hit the spark plug from inside? All other plugs are unaffected.
Should I be looking deeper into this?
Any input or advice would be appreciated.