how do i empty the radiator to change the antifreeze?

do i have to loosen the bottom hose to let it drain ? i was wandering if that was the only way ??

i found it. It's a plastic valve, boy do i feel stupid !!

No need to feel stupid. We've all been there at one time or another. Glad you found it. Be sure to bleed all the air out of the system when you refill it to avoid overheating problems. It can be a bit challenging so be persistent.

Where did you find it? I’ve been looking for days!!

Bottom of the rad on either the passenger side or driver’s side, I can’t remember. I believe you may have to look up through an access hole. If you’re still having trouble, drive the car up on some blocks and get underneath with a good work light or flashlight.

2006 Chevy cobalt does have a drain pitcock, it's on the bottom of the radiator passenger side back towards the tire

Trust me I've replaced my whole cooling system on mine and I'm very familiar with it at the point and it is a pain to get all the air out so keep at it.