How to Drain and Add Radiator Fluid

Radiator Fluid being poured
  • 1-2 hours
  • Beginner
  • 30-50
What You'll Need
Vinyl gloves
Catch pan

You probably spend relatively little time thinking about your car's radiator fluid, but did you know that a simple procedure like keeping your car's coolant at the proper levels can save you time and money by avoiding needless breakdowns and repairs? Often, your coolant is the only thing preventing your car from breaking down. In addition, radiator fluid must be replaced regularly. Luckily, both maintaining your radiator fluid levels and replacing your coolant are simple and quick procedures, at least once you are equipped with the proper knowledge. If you do not know how to drain and add radiator fluid, here are some basic instructions that should be useful.

Step 1 - Checking the Levels

Before you do anything, you need to check your radiator fluid levels. If you have used your car recently, wait a minimum of 30 minutes for the engine to cool down. If you have not used it recently, or you have waited long enough for the engine to cool down, you may continue.

Pull the hood release lever under your dashboard, then use the latch on the front of your car to pop the hood open. Use the prop rod to secure the hood, and look for the fluid reservoir. It should be a partially see-through white plastic container next to your radiator. You should be able to see the level your fluid is at by looking through it. Since your engine is cool, your fluid should be at the level marked "cool."

Step 2 - Adjusting

If your fluid levels are low, you may want to add fluid and call it a day. However, if you are trying to drain and replace your coolant, skip this step.

Radiator fluid is a mixture of equal amounts of water and antifreeze. However, some products will come pre-mixed. Always read any instructions carefully, including those in your owner's manual.

Use your funnel to add the appropriate amount — again, probably half water, half antifreeze — to your tank. If your car breaks down, stranding you in the middle of nowhere, you can add pure water, but this is a temporary fix and should only be used to get you to a place where you can remove this water and replace it with real coolant.

Step 3 - Draining

Put on your vinyl gloves. Locate the radiator drain valve on the bottom of your car. Set up your catch pan below it, and open it. Be sure to keep children and pets away from antifreeze, because it smells good enough to eat, but is actually poisonous, even in small amounts.

Disposing of old coolant will be different for you depending on your location, so ask the local authorities how to do it best.

Now it is time to flush your system. Close your radiator drain valve. Open your hood and fill your reservoir to the appropriate level with distilled water. Close everything up, then run your engine for 10 minutes. Wait for everything to cool down — roughly 30 minutes — and then drain the system again. Repeat until nothing comes out but water.

Now, mix 1 part antifreeze and 1 part water in a third container. Add this to your reservoir. Now, leaving your cap off and hood open, run your engine and allow it to idle. Keep adding your coolant, at a rate of no more than 1 liter per minute, periodically squeezing all parts of the radiator hoses. Air should escape through the reservoir. When you cannot add more fluid, you are done.