ok so i have a few fans in my pc one in front and some in back but i can not tell wich ones are sucking air in or pushing it out...is there a way to tell?
Yea, put your hand in front of them. If you feel a breeze, it's blowing towards your hand!
Generally, they blow away from the open end, or the spinning part of the fan enclosure. There may also be a small arrow on the side of the fan enclosure showing the direction.
Most quality fan manufacturers have and arrow on their fans, trouble is, if the fan is already installed with the arrow no visible and you do not wish to unscrew it you'll need to use something like the above method.