How To: 2nd Gen 4Runner Heater Core Replacement

It seems that there is no information on heater core replacements, I have just completed this action and wanted to share this information for individuals who are in need of tackling this task.

In order to remove the heater core the entire dash needs to come off and the compartment that the heater core is surrounded by needs to come out otherwise you will still be smelling coolant when the heat is on. There are a variety of screws and bolts on both the driver and passenger side that need to be removed to begin this.

The odometer also needs to be removed which will give you access to 2 more bolts securing the dash. Begin to gently pull the dash and it should pop out of the clips near the windshield, if it does not, figure out where it is being held because you will miss screws they are everywhere.

After you remove the dash you will see a large white and black plastic compartment in the center of the dash - the heater core can be seen from the pipes entering the firewall almost directly in the center. In order to remove this the metal bracket that secures the radio/temperature controls/electronic equipment must be removed as well. There are bolts on either side (12 mm) as well as under the carpet near the gas pedal and the left side on the passenger side. You need to pay attention and remember how the metal wires going from the temperature control panel to the heater core compartment are placed (take pictures/videos whatever works for you). If these are placed incorrect the heat/AC will not work properly opening different flaps/blender doors etc.

You must remove the hose clamps near the firewall in the engine bay (somewhat tight due to the intake manifold) before anything inside of the vehicle is able to be removed. Before you being to tug and pull on the hoses, use a pair of needle nose vise grips or clamps on the hoses near the connection point to the heater core so you do not loose a lot of coolant. Place a catch pan under to vehicle almost under the front differential to catch any coolant that it released. The hoses on my heater core on mine where pretty well stuck due to years of sludge/corrosion/everything else so I actually had to make a cut on the hose to get them loose. It will drain a little coolant from the heater core when this happens. You can begin to maneuver the compartment out (I had to remove the white cover first) without spilling any coolant inside of the vehicle - just be patient I swear its possible.

When this has been removed the heater core will slide directly out. Make sure you wash and dry the compartment out before re-assembly or the coolant smell will still linger around. There are some foam pieces inside the compartment, I would also let those dry before reassembly.

Before putting the heater core back into the compartment, fill it with coolant and make sure there are no leaks because...that would suck. If everything checks out and the compartment is dry, reinstall the heater core and complete the steps over again.

Also it is probably not a terrible idea to clean all the vents out and the carpet under the heater core/passenger side because I'm sure has coolant on it which is why you're doing this. I also recommend going to a pick n pull and trying this out (if they have a 4runner) there first before completing this - this will give you an idea about the difficulty of this project as well as hands on guidance before tearing apart your own 4runner. I hope this helps anyone in need - I apologize for not taking pictures during this process.

 

It takes a solid 3 hours to remove without breaking anything. Its a weekend job for sure.