Originally Posted by protect1989
What they found in my case was that the dealership who did my last oil change put on two filter rings instead of one.
My accurately, what they found was that the old filter ring stuck to the vehicle when the old filter was removed, which resulted in two being there when the new filter (including a new ring) was installed.
While rare, it's not unheard of to happen. In fact, if it were more common, the guy doing the change would have likely been conditioned to check for the issue. It actually happens quite a bit on motorcycles with spin-on filters.
I've always checked to be sure the O-Ring comes off with the old filter just because I had a friend have that very issue happen. Thankfully, the oil opted to start weeping out right away after he fired the car up and did a leak check. At first, he thought he had a defective filter.
I actually spotted that very thing happening with a filter on my last truck once. When I pulled the filter off, I noticed there was no ring. I checked the truck and there it was - stuck to filter coupling.
Just something to watch out for when doing your own changes. In the case of those who have someone else do it, it never hurts to peek down there and check for leaks ans weeps. You never know when they might fail to thread the plug in correctly or fail to replace a crush washer.