You actually get more oil out when extracting from the top than you do draining it from the bottom. This is the way the dealerships do the oil change as well. So many uninformed people on the forums are always chirping in that "No way you can get all the oil by extracting from the top." Absolutely not true. One of our Crossfire members on the forum had to do maintenance on two Crossfires where he was replacing the oil level sensor so he had to drop the oil pan on each car. So he used that to experiment and compare. Before removing the oil pans, on one car he extracted the oil from the top and on the other car he drained the oil from the bottom. Then he dropped the oil pans and checked to see how much oil was left in the pan. There was almost no oil in the pan of the car that he extracted the oil from the top. The pan from the car that was drained from the bottom had more oil left in the pan. It wasn't much, but 3 or 4 ounces but it was more and that's because of the baffles in the oil pan that hold some of the oil and it doesn't go out the drain hole. So this method is valid and superior. There's a reason the dealerships do it this way.
All the Crossfire owners I know are fully aware of the 5th O ring but like me they choose not to change it. That is because to get to it you have to separate the top of the oil filter stem assembly from the stem itself. Doing that there is a very high likelihood of breaking the stem where it attaches to the top of the assembly. That O ring is not critical and not worth risking the damage to the stem assembly so we don't replace it.
