For a month now on warmer than average days (meaning about 0 degrees celcius) I have been leaking coolant while the car sits overnight(1982 300sd). When I come out in the morning there's a drip off of the base pan that very steady. When I look at the water pump there isn't any coolant coming out of the upper weep hole but if I look below the pump there is coolant dripping from there onto the harmonic balancer. First off is it possible for coolant to only leak from the bottom weep hole or is this most likely a gasket issue? Secondly, is it wise to use one of those form a gasket products or do they work at all? Thanks in advance Mike J.