This is somewhat related. My wife used to have a '00 Sportage that the vc leaked twice. Twice it developed a leak that filled the spark plug hole with oil, that cause the plug to miss fire due to being submerged in oil. The first replacement didn't have sealer on it, but the second one did. This happened at 90k and 100k,and under the valve cover was so cleaned it looked like it was put together the week before. Mobil 1 EP since 10k.,,,