I changed the oil yesterday on my new 82 745i. This has a bottom-bolt cannister. There was only an oil filter inside. All my e12s with bottom-bolt oil filters cannisters had a spring and cap inside them, holding the filter up to the top. Does the e23 also require such parts inside the cannister? I have them in my stash in CT. They were always missing on every e12 I ever bought, a result of "mechanics" not knowing what to do with them when they changed the oil!