[dangerous]

I made an aparatus using an old upper cooling hose and some plumbing pieces that enabled me to connect a garden hose. I then attached the original hose end of the apparatus to the head, upper radiator, & lower radiator connections. Let's you flush in both directions. The detergent suggestions already mentioned are great though. If anyone is interested, I can take a photo. It's a frankenstein looking thing because just used whatever I had available....but it works.