How to Check and Add Radiator Fluid

Regularly checking and adding radiator fluid is necessary to avoid expensive engine repair.  Anti-freeze raises the boiling point of water, thus pulling heat away from the engine.  It also has a lower freezing point, keeping the water from icing in winter.  Many people run their car with water in the summer, not realizing antifreeze keeps the water from evaporating. 

How to fill the radiator of a newer ( 1970's and newer ) car.

1. Open the overflow reservoir while the car is cool if  you are driving a newer car ( post 1970's ).  NEVER open a radiator cap or overflow reservoir when the car is hot.  If you have been driving and need to check the water, allow the car to cool at least one hour before opening reservoir or radiator.


2. Open the hood of the car.


3. Locate the fluid reservoir next to the radiator.  It should be a semi-clear container with green or red radiator fluid in it.


4. Unscrew the reservoir cap.  Add a bottle of 50 percent / 50 percent mix radiator fluid to the "full" line.  Do not over-fill. 


5. Screw reservoir cap back on.

If the car is severely overheating and you have no radiator fluid, you may use water.

If the temperature gauge spiked to the red line, pull over and allow the vehicle cool down. Do not drive while hot.  Follow steps 1-5.  Slowly, take it to where you can park it.  Have a qualified mechanic look at your car as soon as possible.

How to fill the radiator of an older ( pre-1970's ) car.

1. NEVER add liquid to a car that has been recently been driven.  Allow the car to cool at least one hour before opening the radiator cap.  The liquid builds up pressure and can spray scalding fluid causing severe burns.


2. Open the hood of the car.


3. Locate the radiator cap on top of the radiator, usually on the right hand side near the hood latch.


4. Press down and turn to loosen the radiator cap.  Do not remove completely.  Allow any pressure to release if the car is hot.  If the car has been sitting, you may remove radiator cap without hesitation.  You may need to use a couple of  rags or a towel to protect your hands and to grip the radiator cap.


5. Look into the radiator.  If the fluid isn't visible at the surface touching the cap, add coolant.