93 Maxima oil leak at timing belt cover

I noticed a good sized oil leak coming from my moter. Upon inspection, I found the oil was coming from the place where the top timing cover and the bottom timing cover meet together. I found one bolt was missing at the bottom of the top cover. I replaced the bolt but it still leaks there. Some people say I need to take the top cover off and reseal the cover, using RTV. If this is true, please take me through the process of getting the cover off. Also, there is a metal shield behind the timing cover. Does the metal shield need to be sealed to the front of the motor? Please explain the procedure in great detail, so that I may fix this leak. I would especially appreciate response from a Nissan technician. Thank you, in advance.