[nukezero]

It's going to be time soon to replace the spark plugs the 2nd time, 1st time by dealer.

I be reading some horror stories that some people have broken off the ceramic and snapped the spark plug inside the cylinder. This would undoubtedly cost thousands to fix.

I'm trying to understand and weigh in the risk and cost of doing it myself to save money, versus paying the premium to have the dealer do it and let the dealer assume all this risk.

I understand this isn't like when I change the oil, brake pads, oil filter housing gasket, or the water pump, those I did all myself and the risk is low. But this simple spark plug change could catastrophically set me back thousands if something goes awry.

Now does anyone know, what causes the spark plug to just snap off like that? Is it during the install or is it during the removal? I can't seem to fathom why it would snap off so easily.