Close up of Lincoln mechanic adding engine coolant

When your engine is running, it makes power—but it also makes heat. And that’s where engine coolant comes in.

Coolant circulates through the engine and absorbs heat, helping keep the engine at the right operating temperature.

Coolant also helps keep your engine working as efficiently as possible, helps keep its emissions low, and even helps provide that toasty heater air on cold days.

You should check your vehicle’s coolant level every time you fill up the fuel tank. And if you ever need to add coolant, here’s how to do it.

Before you start

  • Check the owner’s manual to find your vehicle’s correct engine coolant—different engine types require different coolants.

  • Locate or buy a gallon of the correct coolant.

  • Roll up or remove loose clothing, and keep your arms away from the cooling fan(s). Fans can turn on automatically, even when the engine is off.

  • Never remove the coolant reservoir cap when the engine is running or still hot. Let it cool down first.

  • Put a towel or a thick cloth on the reservoir cap before removing it, as the cap is under pressure.

  1. Make sure your engine is off and cool, the vehicle is in Park or Neutral, and the parking brake is set.

  2. Open the hood and locate the engine coolant reservoir. It is often a translucent white color, and has hose(s) connecting it to the radiator.

  3. The reservoir has a fill range marked on the side. If your engine is cold, the coolant level should be up to the cold fill line.

  4. Loosen the reservoir cap just a little, then step back while the pressure releases. Then, remove the cap completely.

  5. If the coolant level is low, add the correct coolant to the reservoir (not the radiator itself). You can use diluted coolant by itself, or a 50/50 mixture of concentrated coolant and distilled water.

  6. When the coolant rises to the cold fill line, replace the cap and tighten it until you feel it click. Close the hood.

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