I know this is an old add but I would like to put my input if I can, I just did my heater core, I bought all the parts from Napa Auto parts, my heater was not working properly and I was debating if I wanted to do the work `cause unlike you guys I had to take the hood and the fender out . It took me at least ten hours to do the job by myself , me been anal, it turn out to be that there was a mouse nest, it really look like someone blew a pillow inside the core unit they got in throu the heater fan, My advise is while you are there replace the heater fan and also put chicken wire around the fan hole so those little basters don`t get in there again. I am glad I did it my heater works the best and it does`nt smell like pee.