The nut must be really tight to prevent the water leak. I have had to remove the battery tray in order to get good access to it. On one tractor I even had to grind some metal off of the head to get the wrench on the nut good. If you are using a drift and mallet to tighten it I suspect you're not getting it tight enough.
I haven't tried tilting the hood but it must not work because I've never read on this forum of anyone doing it.