I changed one of the spark plugs on my 2015 Subaru WRX at 95,000 km. Subaru recommends changing the NGK Iridium plugs at 100,000 km. Other auto manufacturers seem to usually recommend 160,000 km for these plugs.
I only changed the one because I managed to get a rubber grommet from a spark plug socket stuck on the original plug (socket was a size too large), and by the time I fished it out I had hit my daily quota for blood, sweat, and tears. Once that was dealt with, the old plug came out easily, despite being in there for 10 years.
The gap of the old plug was still right within the original spec of .020 to .022". The only thing that doesn't quite look right to me is the end of the ground electrode, which seems to be a bit deformed or worn more on the one side vs the other (2nd and 3rd pics). The plug was removed from the most knock-prone cylinder. I was hoping that replacing the plug would reduce the knock readings, but it had no effect.
The last pic shows a small amount of oil in the spark plug well. The ignition coil didn't feel oily so I don't think it's being dripped onto. I don't think it's easy to replace the spark plug tube gaskets on these boxer engines, so I think I'll just pretend I didn't see it.
I think the plug I removed looks good enough that I'll keep the others in for a while longer. What do you think?
I only changed the one because I managed to get a rubber grommet from a spark plug socket stuck on the original plug (socket was a size too large), and by the time I fished it out I had hit my daily quota for blood, sweat, and tears. Once that was dealt with, the old plug came out easily, despite being in there for 10 years.
The gap of the old plug was still right within the original spec of .020 to .022". The only thing that doesn't quite look right to me is the end of the ground electrode, which seems to be a bit deformed or worn more on the one side vs the other (2nd and 3rd pics). The plug was removed from the most knock-prone cylinder. I was hoping that replacing the plug would reduce the knock readings, but it had no effect.
The last pic shows a small amount of oil in the spark plug well. The ignition coil didn't feel oily so I don't think it's being dripped onto. I don't think it's easy to replace the spark plug tube gaskets on these boxer engines, so I think I'll just pretend I didn't see it.
I think the plug I removed looks good enough that I'll keep the others in for a while longer. What do you think?
