I've not seen anyone mention using the old Prestone flush n fill kit. I've got one out in the shed I bought a few years ago and never installed. I've put one of these flush kits on almost every vehicle I've owned, anybody put one on their Runner??
Just did my this week using Prestone flush n fill kit, make sure you find the input heater core it's in the middle of the firewall.You can't miss it while I'm there I also flush the heater core hose as well.