You have air in the system. Don't turn the wheel with the engine off.
With the engine running turn the wheel lock to lock. While holding the wheel against the steering stop shut the engine off, when you release the wheel it will push the air out and must likely overflow. The idea is to restart the engine before it overflows and turn the wheel to the other side and repeat. After a couple of times it won't overflow but don't let it run low or it will get air in it again. Keep doing this till it you feel like it is not going to overflow anymore | 
