Take it to a garage and let them have the headache!!!...you need to disable the airbags..do this by unhooking the battery...then drop the steering column...everything needs to come out as far as the dash goes...remove clips or screws (which ever you have) on the heater box...disconnect lines going to heater core...slide heater core up and out of heater box...before reinstalling the new heater core...my suggestion would be to thoroughly clean heater box or smell will remain as antifreeze is oil based and won't fully evaporate...make sure lines are clipped tightly...I did this with a flush kit and garden hose before I went through the 4 1/2 hour reassembly hassle