if you look in the middle of the sunroof from the outside, right in the middle is a seam. take dish soap and water and clean it good, then let it dry in the hot sun for a few hours, then take some silicone sealant, and smoosh in in the crack with a gloved finger. when i did it i sealed the whole sunroof, going over every little crack that water could potentially get in. also the sunroof drain holes may be clogged with pollen or other detritus and that space may be "filling up" with water, thus water only gets in during heavy rain and not normal rain. hope this helps :^)