I would not JB Weld the tank even though JB weld is great for alot of things however being that the cooling system on the Northstars is pretty important i would just replace the tank. I had a small leak in mine like two years ago it was a very small leak and it took me like two weeks to find. Because the coolant was squirting into the serpentine belt but you could only see when you would accelerate the car. Well to make a long story short a brand you tank cost me about $90-$100 plus labor i paid like $160 total. because i looked at doing it myself but you have to remove the accumulator in order to get the tank out and replace which you will then probably have to recharge your a/c at least i had to do that after mine was replaced.
Good Luck!!!
