I'm somewhat concerned about the post that runs through the middle of the filter, and the nut on this post that is on the top of the filter housing. I'm not sure if I need to tighten this or loosen it, or what to do with it. I'm not certain what purpose it serves, and I didn't know what to do with it. I know that I did not replace these O-rings, but I can't imagine that this has caused me to lose 2 qts. or oil over the course of a 15 mile drive.

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86 300 SDL (201,000 miles)