Just in case you don't know.
Do not seal any GM products to protect them from waterThey will end up with more water in them from condensation and go rusty.
I tried to seal a motor to make it air tight, and the results are always the same. RUST and water inside. I unsealed it and cleaned it up and repairs, and years of use through puddles over the wheel axel and guess what? no water and no rust.
Seal it and you get a problem with water, unseal it and the problem goes away.
Seal it up again and water comes back. Its like the tide man, you can count on it.