Here is a neat little pictorial diagram I found on the google search showing the roof seal gasket...
Mine got so lose one time I almost lost the top unit...
I think the rule is to depress the roof gasket just an 1/8-inch or so by tightening down long the four long bolts.... Probably vibrations and old age of the roof seals are the problem.
I also get dripping from my air conditioner when it freezes over some. This usually happens in the middle of the night when it is very humid outside... I found keeping the blower speed on high keeps this from happening...
Roy Ken
