I just put a 12 oz bottle of Marvel Mystery Oil in my 95 BMW 525i with 172,000 miles. I have already done 3 Auto-rx treatments. Thought I would try soemthig else. How long should I leave it in or can I leave it in for the remaining fill? Currently I have 10w40 mobil 1 truck oil with about 3,500 miles on the fill. I have a random hot idle tapping-like a sticky lifter-that comes and goes.