Reading the description of the suction pump, it sounds like it needs a good seal on whatever it's pumping in order to suck? Anyway, is that where you put it, in the drain plug on the right side of the block, after gravity draining it? Or use the pump to suck it all out from the beginning?
Sorry for all the questions...just want to get it right. I don't think I've ever drained all my coolant, and probably should if I'm going to flush the heatex with a rad cleaner.