how hard is it to replace the heater core? it started leaking outside of the car a couple months back,im guessing it was the return line, but we bypassed it with a t fitting since it was summertime, well now its getting cold and i need to find out how to replace it, what are the easiest ways that my boyfriend can fix it so i have some heat? 
also,when it was leaking, it would start over heating while driving,it never went into my floor board and every time i stopped i had to fill it up with water again and it would pour out....i read another post and it said that if it was the return line then i would still have heat....im confused
 
There is no way around it. 
The heater core is located under the dashboard.
Get a day off, tools, an instruction manual, some beer, and HELP from someone who knows what they're doing.
