How hard is it to change out the heater core? Are there any guides you could point in my direction? On my way home from work today I smelled coolant inside the car and when I looked at the passenger floor there was some coolant on the carp[et and a slow drip. IWhen I pulled over I could hear the hot coolant escaping from a restriction and there was also a small puddle under the passenger side. I am going to loop the lines together for now to keep the coolant from going into the heater core. Any suggestions?