Overheating RS

car was running fine so when i was changin the oil i decided to flush the radiaor out and run some of this ICE stuff to keep it even cooler...now its been overheating alot more...just in 1 day the entire radiator was empty again...and i cant find a leak anywhere...my guess is it keeps flowing out my backflow resevoir and leaking out there. any idea what i should do? i was thinkin of saving up for a new radiator or somehting to improve my cooling b4 i really started mod'n out.