I had the same problem with my danner leaking. I fixed it with this.
http://www.permatex.com/auto/autouh....&item_no=22071
probably the same thing you're talking about using. Danner seems to be a good pump. My girlfriend accidentally shut the fans/comp off without shutting off the tec, and the water got warm enough to make the pump dump all the water out. Probably warped the plastic housing some, but it runs fine after a reseal with the rtv liquid gasket. :shrug:
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Currently using one large rad, two gallons of coolant, and two 13.5 inch fans to cool my car's engine.