I cant find the antifreeze leak?

[1996X]

Ok, so it started out my brother was driving his 1989 Ranger and it started to over heat. He brought it home and we checked the antifreeze level and it was really low. So we filled it up. The next day we checked it, it was empty again. So we started looking and took it to the mechanic who then gave us a dye to put in and see if it was the head gasket leaking or something. Well its not and it is not burning it off because the exhaust is supposed to smoke if it is with that dye in it. The radiator was leaking pretty bad so we replaced it. and now its not leaking but the truck is still loosing antifreeze really bad.
WHAT COULD THIS BE? Im tired of having him drive my explorer back to college with him.
You guys are the best people to go to so i figured i would ask you guys.
What are some suggestions to find this leak?

 

[1996X]

nobody have any suggestions?

 

[RangerX]

pretty impatient, aren't we?

Give it a day or three, it's Friday night.

 

[1996X]

The reason im being impatient is because hes gonna have to take my baby (explorer) back to college with him for another couple weeks if we dont get it fixed this weekend.