The radiator in a 2000 Ford Ranger should be filled to the
bottom of the radiator's neck. There's usually a "low" and sometimes a "high" mark or a minimum and maximum fill line indicated on the radiator itself, or on a nearby overflow reservoir.
Do not overfill. Overfilling can cause pressure buildup and leaks.
Always refer to your owner's manual for the most precise and accurate instructions specific to your vehicle's cooling system. The manual will show you diagrams and clearly indicate the proper fill level.
