When I recently changed the plugs I found oil in one of the spark plug tube son my 94 Honda Civic. I’m trying to figure out where the leak is. Is it the piston rings, valve seat, spark plug tube o-rings, or head gasket? Also how can I tell which one it is? Thanks
It is probably the o ring. Remember, if the oil is on the ouside of the engine, t is not everything else you have mentioned.
The O ring. This is not uncommon.