2013 Prius v (lowercase v for the Prius v wagon) coolant drain problems

I recently bought a 2013 Prius v (lowercase v for the Prius v wagon) from a private party. The car has been in a front end accident but it has been fixed. When buying the car, i did not notice that the coolant in it was green.

I know that prii of this year run on Toyota pink, and i have also read that mixing coolant can lead to sludging and clog your system. So now I am trying to do a total flush and refill. I already have the pink coolant and I was able to drain about 5 qt (7.3 qt total capacity) from the radiator cock. I have read the forums about the existence of an engine block cock which would allow me to drain the rest of the coolant. But no matter how much i look I can not locate it. Ive read the repair manual, and the forums, I know that is is supposed to be in the back of the engine half way up the block or so. But i just cant find it. I cant fill my car until i can do a proper flush. I really hope someone with the knowledge can help me out here because I do not know what to do at this point. Appreciate the help.


This picture is from my car, i don't seem to have the cock, but bolts instead. Does anyone know which of these two bolts is the plug that is replacing the cock in my case?