When I called the BMW dealer to find out, what is the approximate lifetime resource for spark plugs and after how long mileage they have to be changed for N53 engines, the answer was – the resource is not regulated. When regular misfire starts – well, it’s time to change spark plugs.
I didn’t went thru TIS, found only an image, which shows excessively used spark plug.
Insulator bun-out around the central electrode is not permissible. I highly question the scenario, which is visible in the image, because the central electrode is without burnout marks (it burns out first).
