I was in the same boat. Get a piece of 1/4" line and stick a screw in one end with a hose clamp around it, and stick the line on the return tube with another clamp. The screw should be wide enough that you need to thread it in, and make sure the clamp is very tight. After you get everything on, drive the car to get the engine hot, then park it and keep an eye to make sure the line does not leak.