I have a 02 Montero Sport and I think the heater core is going bad. I have coolant leaking inside, mostly under the carpet on the driver side. I'm trying to change it out myself, but I'm having a little difficulty. Any knowledge?

 

Not sure about the R&R process but also consider/check if it's the rubber hoses running from the firewall to the heater core. Cheaper fix if it is.