My new-to-me truck has an oil leak at the back of the motor on the driver's side. I've felt up there and it seems to be coming from the where the fitting for the oil pressure sender screws into the block. I pulled it out (a royal pain in the butt - thanks GM engineers ) but i can't get it tight - when it is in the right orientation for the sender to screw in - the fitting isn't tight. But I can't get it turned another full turn. I put it back together with some teflon thread sealer - but it is still leaking a fair amount. Any ideas? There isn't anything else up there that could be leaking is there?