coolant drain and water pump

I have a 99 ga gt v6 and was looking for the drain plug on the radiator. i found a plastic piece on the bottom right corner of the radiator that looks like it needs a special tool, is this right? i am also wondering how to get at the tension arm for the serpentine belt it is in an ockward place. and last but not least are there any other plugs for flushing the engine block.

radiator drain plug should be a plastic flat butterfly looking thing lower driver side i believe... as far a the tensioner goes, are you trying to replace it? if so, may have to remove the coolant resovoir, i dont remember any special way to get to it, try taking the fender shroud off to try to access it. ive got skinny arms so im able to squeese in where i need to...sorry im not much help on that. to flush the block ive always just dumped the coolant with the engine running and constantly refilling till i get pretty clear water...dont know of any plugs...good luck