The radiator in a 1998 Ford Expedition is mounted in the front of the engine compartment, directly behind the grill. It is designed to reduce the temperature of the engine coolant and transmission fluid. As radiators age, dirt, debris and other contaminants build up inside, restricting the flow of coolant. This restricted flow dramatically reduces the effectiveness of the radiator. To restore the radiator to its original operating condition, it must be drained and flushed completely.
Turn off the engine, and place the transmission in park if it's an automatic or first gear if it's a manual. Apply the emergency brake, and open the hood.
Place a rag over the radiator cap, and slowly unscrew it, allowing any excess vapor or pressure to escape. Remove the cap completely.
Crawl underneath the truck, and remove the hose clamp from the lower radiator hose using the flathead screwdriver. Place a bucket underneath the lower radiator hose outlet. Remove the lower radiator hose from the radiator and allow the coolant to drain out.
Remove the clamp from the upper radiator hose using the flathead screwdriver. Remove the upper radiator hose.
Place a garden hose inside the upper radiator hose inlet, and turn the water on. Allow the water to flow through the radiator and out the bottom at the lower radiator hose outlet. Continue pumping water through the radiator until nothing but clean water, free of dirt, debris and old coolant, flows from the lower radiator outlet.
Switch the hose to the radiator cap inlet, and flush water through the radiator again. Continue flushing until the water exiting the lower radiator outlet is clear. Reconnect the hoses, and refill the radiator with engine coolant. Replace the radiator cap, start the engine and check for leaks.
