Why is 1992 Toyota 4Runner overheating?

Answer 1

3 possible causes that come to mind right off. Easiest is the thermostat is sticking and not allowing fluid to flow from the motor to the radiator. Try replacing this first.

Second is the radiator is clogged and not cooling. Some models allow you to have them cleaned internally by a professional. Usually cheaper to do this than replace the radiator. But if you cant clean it then replace it.

Lastly is the fan clutch is broken. The radiator needs a steady flow of air to remove all the heat generated by the motor. The fan clutch will increase its speed as it heats up. So a broken clutch never speeds up enough to let air flow through it.

Needed to add that if you are using a hose with an internal metal coil. Get rid of it. The coil has a tendency to rust. This rust carries to the radiator and clogs it up.