Unfortunately I have to Agree with Mark to a point. In your situation, I would say the radiator should be paid for in full before shipping PERIOD! It's nice to trust people but unfortunately morals and ethic's have changed.
As my wife has said, you don't go to the grocery store, gas station, or Walmart and say I'll send a check next week. 50 years ago maybe, but society has changed and you have to change with it business wise to survive. I do hope you get paid