[bmw-extreme]

While replacing glow plugs I noticed that M47 and M47N2 engines' glow plugs are not exactly the same. M47N2 glow plug has a designation groove. When I tried to install the M47's glow plugs to M47N2, I couldn't tighten them in properly. Every time I try to tighten them they get stuck halfway through. Greasing etc. does not work. But, when I again install the old one, it goes all the way without any problems. Yes they look same, however threads of both glow plugs are slightly different I think. 🤔