If it's rattling, you need to get that oil pan off and inspect the bearings, before your annoying noise turns into a hole in the block where a locked-up connecting rod came through. If that means pulling the engine, so be it. It's possible a bearing change now might avoid a crankshaft replacement later. If the crank is worn out of round or tapered, it needs to be reground and proper-sized bearings installed. Let it continue to knock, and you'll end up with a boat anchor instead of an engine.
Jerry
