I have a 1999 ford explorer 4.o L v6 . I had hate but but herd a pop . Then no heat ,I just change the thremostat still no heat ,I ran the motor 5 to10 min with the radiator cap off to getair out. So now ,no heat e-mail [email protected]

Is the engine warming up?

Have you tried blocking the flow of air to the radiator by using cardboard ? Not a perm fix but it may artificially allow the engine to warm up.

It could be your water pump is starting to go.

You first need to determine if the problem is that the heater doesn't work or if the engine is not warming up. If the engine is warming up and you block the radiator, this could turn out bad.

It could be that the heater box door isn't opening but we won't know that until you come back and fill in the details.