The radiator, fan and coolant reservoir tank are the three components that make up the coolant system. The coolant system in your car or truck distributes a water-coolant (otherwise known as antifreeze) solution through your car. This keeps your vehicle from overheating. The temperature gauge in your vehicle reads information relayed by the coolant tank sensor. This sensor is installed inside the radiator and monitors the temperature of the coolant inside. If the sensor breaks or fails, you can replace it at home inexpensively.
Open the hood of your car or truck. Loosen and remove the negative battery cable with your wrench.
Make sure the radiator is not hot. Never work on the radiator when it is still hot, or even warm.
Access the radiator drain plug. On some makes and models, this will be as easy as bending down and finding the plug at the bottom of the radiator. With some models, though, you may have to remove the plastic radiator fan shroud to get down to the drain plug. The fan shroud is held in place by plastic or metal nuts lined up along the top of the shroud. Remove them with a nut driver set and pull the shroud up and off.
Slide the drain pan under the drain plug and open the plug. Allow all the coolant to drain out. Screw the drain plug back in and tighten it with your wrench.
Pull off the wiring plug from the back of the coolant tank sensor, which is mounted into the side of the radiator. Use a wrench to remove the sensor, which screws into the side of the radiator similar to the way a spark plug screws in.
Screw the new coolant tank sensor into the radiator. Plug the wiring plug back in.
Open the radiator cap, start the engine and add the proper mixture of coolant and water to the radiator. These mixtures will vary with different makes, models and style of vehicles. Consult your owner's manual or your vehicle dealer to find out the right mix if you do not know it.
Replace the radiator cap and replace and then tighten the negative battery cable.
