Roofing tar can help the repair.

"tom" wrote in message
ups.com...
If the tab came from a spot where the underlying shingles butted
together at their ends, yes, it'll leak. You can temp over it with a
flasher, or a piece of roofing felt. If the tab came from a "better"
spot, the fasteners will present a leak problem soon. Piece 'o cake to
fix, usually. Tom