I found a leak around the dipstick tube entry into the oil pan after switching to synthetic. I tried to pull the tube out to replace the o-ring. Was unable to pull it. I only pulled it out 1/4" or so. Gave up and decided to go back to dino oil and little heavier weight. Drove car all day and was going to replace the oil in it tonight. Got under car to drain it and found no sign of oil leak. I don't know if maybe I reseated the o-ring when I was attempting to pull it, or if the syn oil finally conditioned the seal. Anyway, it's gone and I'm happy. Now on to thrust-arms next weekend!