Your 2000 Ford Taurus has four sources that may leak water. These include the cooling system, windshield washers, air conditioning and weather. A water leak may signal serious trouble on the horizon. Check with your Ford service department to see if there are any recurring issues to look for. It's possible a service alert or recall was missed which may remedy the problem. You should always eliminate the easy to diagnose items first. Begin by moving the vehicle to a level, firm surface. Park and leave your Taurus there for at least two hours if it's hot.
Windshield Washer, Air Conditioning and Weather
Insert a funnel into the windshield washer reservoir and fill it. If there is a leak in this component, it should appear on the ground near the passenger's side wheel. Turn the key in the ignition to the "On" position but do not crank the engine. Activate the windshield washers with the hood open to check the hoses.2
Run a hose over the windshield for several minutes to locate any drip points. A leaky windshield seal will allow water inside the car. Wet carpets and a moldy smell are warning signs. A bad heater core or A/C drain hose may mimic this problem.3
Look for a small hose underneath the car near the passenger's foot area. Air conditioning releases water that runs under the floorboard. If the hose becomes plugged, water cannot escape and may create a sloshing sound or leak inside. Push a bent coat hanger into the hose a few inches to remove any obstruction. If the hose is not visible from underneath, it may have pulled inside the car. Check under the dash on the passenger's side to make sure the hose is routed through the floorboard.
Remove the cap on the left side of the radiator. If the water is more than 2 inches below the top, you may have a cooling system leak. Top off the coolant and replace the cap. Check the overfill bottle on the left fender. If it's cracked or wet, that could be your problem. If it's low, fill it to the "Cold" line and close the top. Look over the entire radiator's exterior for antifreeze or water leaks.5
Examine the heater hoses, which pass through the middle of the firewall. Follow them to their ends and check for leaks. Grab the hose ends and gently move them back and forth. Watch for any seepage. Shine a flashlight down behind the radiator cap to see the lower radiator hose. Inspect the upper radiator hose where it joins the thermostat housing and all around the engine for gasket leaks. Survey all hoses, checking for bulges. Tighten all hose clamps with a pair of channel-lock pliers.6
Start the engine. Warm the car up to operating temperature as shown on the dash gauge (about 10 minutes). The water pump is behind the drive belt on the passenger's side of the engine. There's a large pulley directly in front of the pump. If the small hole in the pump housing is wet, it needs to be replaced. Check the gasket for drips as well.7
Turn the heater on high with the engine running and wait a few minutes. If you smell antifreeze, this indicates a heater core leak, which requires expert knowledge to repair. Feel the passenger's side carpet for wetness. This is another clue to a potential heater problem. Replace any lost fluid with a 50/50 mix of water and antifreeze.