the low pressure air condition hose that run from under the radiator.can it be replaced?

It can be replaced. Every part of the A/C system can be replaced. What makes you think that it is causing your engine to over heat?

i have been driving the car now for 6-7 months and it has not overheated once.the air does not not have any freon in now because i rechaged it approximately 3 months ago and it started cooling but started to overheat but there is a donut connection between a brided line and a solid line that popped and the freon drained out.

When the A/C is on, the engine revs increase at idle and some cars have the electric fan turned on to provide additional cooling. You can repair/replace that line and take it to a A/C place for refill. They will draw a vacuum, check it for leaks and fill the system if it is good. I wouldn't think that the A/C is causing the over heating but if the cooling fan is not coming on, it might.

I had the hydraulic fan pump replaced initially because the fan was not operating at its peak performance.