Checking car radiator water levels sounds easy enough, but when you find the cap, it’s covered in warnings. Perhaps you’re not real experienced under the hood of a car, and when you mentioned your coolant light was on, someone told you to open up the radiator cap and check the fluid level. Here’s how to check the radiator fluid in your car without getting scalding hot coolant all over yourself.
Turn off the engine of the car and let it cool for at least a few hours. The cooling system on your car is pressurized, and if the radiator fluid is the least little bit hot it may go spurting out of your radiator cap if you open it.
Lift up the hood and locate the radiator and radiator cap. In most instances this is a shiny metal cap with a warning label on it that goes something like, "WARNING: Do not open while engine is hot!" It's most likely located somewhere near the center front of your car.
Feel the radiator hose and make sure it's cool. If it isn't, wait a few more hours before checking it again.
Open the radiator cap with a shop rag. This will help prevent scalding if your radiator fluid is not quite cool enough.
Look at the radiator fluid level. It should be right at the top of the radiator. If it isn't at the top, add some fluid, but be sure to follow the manufacturer's directions precisely. Some makes of cars require a special coolant or coolant ratio. Most of the time, it's a 50 percent mixture, meaning 50 percent water and 50 percent coolant.
Replace the radiator cap and turn it until it locks, or the pressure from the system could blow the cap off. Look at the coolant overflow reservoir as well to make sure it is up to the recommended level.