My 873 has a engine oil leak i think its dripping from the oil cooler. I can tell where, but itsa from up there. Im not sure if its a seal or the cooler itself. I lifted the top cooler up and out, now i need to disconnect the oil cooler. How do i insure the oil is drained from the oil cooler? Or is it i just drain as much as I can from the engine drain and go from there? If anyone has done this before I would appreciate some advice.