block drain plugs are located both front and rear of the block. They are square plugs, located just above the oilpan, and the middle of the block.

well actually i realized that dex cool is what i have been running for 8 months now, but i am running it on a 70/30 mix...so i need to 50/50 it for summer....then i am gonna leave it that way...

also...that whole block drain thing sounds kinda sorta difficultish and waste-o-timeish....why don't i just drain the radiator, full with water, go run it for a little while, come back, drain, re-fill with water, and THEN add in the 50/50 of dex cool OR WHATEVER i decide to put in...?

They do make some coolants that you can "mix" with whatever you have already.

yeah, i think you can mix dex cool with green crud