I tried to seal as best as I can on top of roof but could not see where its coming from. I was thinking of getting some sealer to use around the inner part and just sealing from teh inside out. I know the vent will lift up enough for me to spread sealer around it. Thanks for any input. Here is a pic of the problem. We had a SEVERE rain today that caused some of the worst flooding we have seen in this area so this is how it looks with super heavy rain. I did not see much hitting the ground when before it was leaking pretty badly so what I did up top did help some.

http://i14.photobucket.com/albums/a3...i/IMG_1123.jpg

 

It's hard to see how it's shingled, what type of shingles you have, or why it might be leaking from an inside perspective. An outside picture would also be helpful.

Personally, I rarely rely on sealants as the main way to keep out water. It's much better to shingle around penetrations correctly, using layers of roofing felt or metal as additional flashings, if needed, to prevent leaks in the first place.

Sealing your vent from the inside is a bad idea, because all that will do is divert the water temporarily and ruin more plywood sheathing in the process.

IMO, you should fix this leak with proper roofing methods by removing and fixing improperly installed shingles and flashing, not simply with more sealant.