I was changing the oil today as I have done 20 times on my X5. This time though when I pull the canister out this little spring with a black plastic cap on it and an aluminum cap that the plunger and spring fit into. I suspect it came out of the hole in the top of the canister housing but I cannot figure out how it goes back in there and I don't want to screw around with the oil supply. Does anyone know if I have to pull the oil pan to fix this back the way it is supposed to go?