I would always carry at least two quarts in the X. I would then make a routine (which should be a common practice), to check the oil every week on a particular day. Saturday morning is when I check and usually clean my cars. If you are driving more than 500 miles a week, then I would sugest checking it twice a week. If it becomes routine you will not forget.

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2001 E53 4.4 Alpine White, Sports Package
2000 E36/7 2.8 5 speed Bright Red w/ a HT!