How to Check and Add Radiator Fluid

Radiator fluid, or coolant, is the most important part of your car's cooling system, which protects your engine from overheating. Low coolant can lead to a breakdown and expensive repairs.

Instructions

Difficulty: Easy

Things You’ll Need:

• Water
• Antifreeze
• Engine Coolants
• Rags

Adding Radiator Fluid to a Contemporary Car

1. Note that only much older models of cars (pre-1970s) require you to add coolant directly to the radiator. Newer vehicles feature a reservoir tank that you can access anytime (except German and Swedish cars, in which the reservoir is under pressure when the engine's hot). If you're driving an older model, see Section 2.
2. Pull the hood release lever under the dashboard.
3. Walk around the front of the car, reach under the hood, find the latch and squeeze it. As you squeeze the latch, pull up and open the hood.
4. Look for the plastic reservoir tank, which should at least be holding some residue of coolant, which is normally green (although there are also red versions available on the market). It's often labeled, located near the radiator and has a hose leading to the radiator.
5. Unscrew the cap and add coolant to the "full" line. Coolant is a 50-50 mixture of water and antifreeze, but you can add stricktly water if the reservoir's empty and your car's in danger of overheating.

Adding Fluid to an Old Car

6. Make sure the engine is cool before adding coolant directly to the radiator. If the car has been running recently, wait at least 30 minutes before unscrewing the radiator cap.
7. Pull the hood release lever under the dashboard.
8. Walk around the front of the car, reach under the hood, find the latch and squeeze it. As you squeeze the latch, pull up and open the hood.
9. Find the radiator cap at the very front of the engine, near the hood latch.
10. Rotate and remove the cap, using a rag. When in doubt about whether it's safe to unscrew the cap, use several rags and unscrew the lid slowly.
11. Look into the radiator. If the fluid doesn't reach the radiator's top just below the opening for the cap, add coolant.

Tips & Warnings

• The hose leading from the reservoir to the radiator is a tip-off that you aren't pouring coolant into your windshield wiper reservoir.
• If the car is overheating, don't try to remove the radiator cap. You could be seriously burned.
• Coolant doesn't get used up--if the reservoir is low, your car may have a leak.
• Coolant is poisonous, but that won't stop pets from drinking it (it tastes sweet to them); don't leave it lying around.