Please fill out the following to ask a question. MAKE: Toyota MODEL: 4 Runner YEAR: 2007 MILES: 142000 ENGINE: 3.6 DESCRIBE ISSUE.... Driver side floor carpet is damp. When I looked under the hood I noticed the heater core location is on the driver side. How difficult is this to change or could this be a body plug that needs to be sealed? I'm assuming it is the heater core because the wife tells me there is a smell in the vehicle along with residue build up over the last month on the front window.