Before you start troubleshooting your Ford Explorer's cooling system, take a moment to clean the front of your radiator with a hose, soap and brush. The tubes inside the radiator can easily become clogged with dirt, which prevents antifreeze from circulating properly. If this doesn't immediately correct your problem, you can check your system with a few simple steps.
Find your Explorer's coolant reservoir under the hood on the passenger's side in front of the engine filler. Check the levels. There's a "MIN" mark on the outside of the coolant reservoir. If the levels are low, add a 50/50 mix of coolant and water.
Run the engine for a few minutes or until its warm then turn the engine off to test whether your thermostat is stuck open. Open your Taurus' hood and locate the two radiator hoses. The hoses are black, made of rubber and connected to the radiator. Touch the top hose and notice if it feels hot. Look for the bottom radiator hose connected to the bottom of the radiator. Touch this hose and notice if it's cold or warmer than the top hose. If your thermostat is working correctly, the bottom hose will be warmer than the top one. If you notice that one hose is significantly hotter than the other, your thermostat is most likely stuck open. If this is the case, you'll need to replace the thermostat.
Look at the radiator cap's condition when the engine is cool. The radiator cap seems like a simple thing, but its condition is crucial to your Explorer's cooling system. A faulty or damaged cap can cause engine overheating.
Check the radiator hoses for cracks and holes. If the hoses are in bad condition, your coolant can leak and lead to the engine overheating.
Take your Explorer to a mechanic to inspect the radiator core. It takes a trained professional to remove the radiator and check for corrosion. Another problem your mechanic can look for is a plugged core. If you notice that the Explorer's engine runs hot while driving at high speeds, this may be the problem.
Listen for your car's cooling fan. The car's fan comes on when the coolant's temperature rises to a certain point. This is an easy step to troubleshoot. Drive your car for 1 to 20 minutes. Park the car and open the hood and keep the engine running. You'll be able to hear the cooling fan. If you don't hear it, that means it's not working and it needs to be replaced.
