Romeo1
Member
The heater core shut off valve is located top and center of the engine bay on the firewall. Here’s what mine looked like. The corrosion and electrolysis ate the hose barb off of the nipple. This 4runner also had a ton of corrosion in it from its past life, if you have a system with a lot of corrosion in it, it may be very well worth your time to check out your valve health.