It's 10* outside now so I don't plan on checking the tightness at the moment but will when it warms up a bit and check above and see if it's magically leaking from there. I did use Permatex Thread sealant High temp 59214 on those that go through. Maybe I didn't use enough, or maybe it was too cold to seal properly?

Here's what I used. Permatex Thread Sealant

 

You may not have used a enough I tend to cover all the threads in through bolts,

 

That thread sealer is the same stuff I used and it worked. Coverage was same as RG above. The bolt hole needs to be very clean too.

 

Regular black silicone works just fine, use liberally.