If you were looking in the radiator cap then it can look rust colored against the black plastic. Its a weird optical illusion. Its should normally be Pink-ish in color unless someone put the wrong coolant in your vehicle.

The 4th Gen 4Runners use a specific coolant blend (Toyota Super Long Life Coolant aka "Toyota Pink") that is made specifically for Toyota vehicles and using a generic "green" coolant can cause serious damage to your vehicle. Toyota's service interval for SLLC is 10yr/100k (for first service) followed by a 5yr/50k service interval.
I would recommend using the correct coolant for your vehicle and not using a "Universal Coolant" as the term is really a misnomer more than anything.