Hi, I have a constant problem with the oil filter seals leaking on my 2.5DT. I have changed the filter and fitted the new seal and tightened the plastic cover but the oil always eventually starts to leak out. If I tighten the plastic cap too much the oil seal gets displaced and oil leaks out. If I hand tighten only the cap starts to slacken itself and oil leaks out again. It seems to me that the oil seals that come with the new filters aren't thick enough for the job. The wife isn't too happy about the patches of oil appearing on the driveway, any suggestions please.