I was polishing my engine today and I noticed one of the bolts on the cover that covers the cam and valves was loose. When I go to tighten it, it doesnt tighten, but it doesnt feel stripped. I pulled the screw all the way out and the threads looked fine. I dont know what to do. Should I just put some loc tite on it and screw it back in the best I can or is it ok the way it is?