1993 Ford Explorer redator

i have not had recent work done and ite gradually problem in know that a mist of steam come from my vents and my defrost doesnt defrost my truck get steamy when im not makie woopie. also i notice that my antifreeze in my residor is milky in color will my car blow up or do i need to replace something also my water temp gauge randomly goes up and down
1993 ford explorer 6 cyclinder 4 door