Yes, JBWeld is the product that makes Liquid Weld. It would be better to get it welded by someone who does aluminum welding as earlier mentioned. We only used it to save the head (a new one was out of the question), which was cracked and too deep for the machinist to machine out. We filled the crack with Liquid Weld, let it dry over-night than he machined it down. Can't say if it worked long term as I sold the car a few months later. In your case if coolant is leaking into the oil, it's better to aluminum weld it

 

Personally, I'd Dremel out the crack slightly to get a good base from which to aluminum weld to. Then have someone weld that sucker up. Have them use welding/heat absorption paste around the crack to minimize heat transfer. Final results won't have to look pretty, just need to seal you up!

Good luck!