I also have the same problem. My rubber seal at the end of the bolt is fine. I changed to Mobil 1 synthetic 12,000 miles ago and this is when the problem started. After a 4-5 hour sit, all the oil would drain back out of the cannister and then when started, my oil light would stay on for 6-8 seconds. Is it my cannister or my oil? I don't know. I changed oil 5 days ago and used Castrol GTX 20W-50. Now my oil light stays on only for 3-4 seconds after I let the car sit. Only this past weekend when the car sat for 2 days did it take 6-8 seconds for the light to go out. I must have a check valve problem, but cannot find out if changing the cannister will really help. Adnan did it on his car but then it started doing it again. Could his replacement cannister be bad?? Somewhere, somebody has to have the answer. John 89 535i 5 speed 105,000 miles