I recently installed a rebuilt 2.5 liter overhead cam engine in my 95 Dakota.. When I was filling it with oil I noticed that oil was running down the bellhousing and dripping on the floor. from the back of the head. I looked at the old engine and noticed that there was a bolt with a large washer installed in the back of the head. I installed that bolt on the new engine and it seemed to take care of the leak. What is the purpose of the bolt and should I have used a sealant on it? I drove the truck today and I may have a leak in that same area. I am going to clean it off tomorrow and see if it is leaking. It is a real pain to get to and I am hoping that it is not leaking..