Whats the best stop leak for a silicone gasket leaking coolant?

[HotDeal]

there is a coolant channel in my front timing cover that is leaking throgh the silicone gasket. I tried prestone stop leak pallets but that only cut the leak by 50%. its only a few drops a night. apparently the pallets are supposed to harden when they encounter air. i stupidly put silicone on the crack from outside which did nothing but it might stop the pallets from coming in contact with air.