As a vehicle owner, you’ve likely discovered at some point in your life a mysterious leak under your car. And if you found yourself at a loss for explanation, you wouldn’t be alone.

What kind of fluid is it? What’s the cause of the leak? Is my car still safe to drive? These are all common questions when discovering an unexplained leak beneath your vehicle. Here are some tips to determine what might be happening and how you should respond.

Confirm the source and identify the color

The first step you should take is to confirm the leak is indeed coming from your car. Use a flashlight to look under your car to identify the source of the leak.

Next, identify the color of the leaking fluid. The easiest way to do this is by sliding a white sheet of paper or piece of cardboard underneath the leak to capture the drips on a clean surface. 


Respond to the leak based on color

After determining the color of the car leak, follow the guide below and respond accordingly.

  • Clear fluid: The least concerning fluid is water. The cause of this may be from the windshield washing system or the air conditioner, leading to water condensation. If you can determine that the clear fluid is coming from one of these two sources, the leak is generally not a concern and can be disregarded.
  • Brown or black fluid: If the fluid is brown, black or amber in color, it’s likely engine oil. To confirm this, touch the fluid. Engine oil will feel slick and hard to get off your fingers. You should never drive your car without sufficient oil, so your first response should be to check the oil levels and refill as needed. Then, visit a mechanic to determine the cause of your oil leak and get a long-term fix.
  • Red fluid: A leak that is pink or dark red in color is likely transmission fluid. This should smell odorless and originate near the middle or front of your car. If you confirm this as the source of the leak, check the transmission fluid levels and refill as needed. Driving without enough transmission fluid can keep the gears from shifting smoothly and damage your transmission.
  • Red or brown fluid: Power steering fluid may be another reddish liquid leaking from the car. You can confirm whether it’s power steering fluid by its smell, which is similar to a burnt marshmellow. If this is the case, check if fluid levels are low and refill as needed. Power steering fluid is flammable, so if you do have a leak, contact a professional mechanic to have your power steering fluid reservoir inspected and replaced.
  • Yellow, green or pink fluid: Coolant is a common source of fluid leaks. This leak would be coming from around the radiator cap, on hoses throughout the engine compartment or on the radiator itself. If it looks like a hose is leaking near a clamp, try tightening the clamp with a screwdriver.
  • Brown, slick fluid: Brake fluid has a slippery texture and is either light or dark brown, depending on the temperature. This leak would originate under the wheels or anywhere near the brakes. While this is a rare fluid leak, it should be taken seriously. Do not drive a car with a brake fluid leak for risk of brake failure. Instead, get your car towed to a mechanic for repairs.


No matter how reliable your vehicle is, a fluid leak can happen and it’s important to know how to respond. In some cases, you may simply be due for a refill. Your local CENEX DEALER is ready to assist with any of your fluid needs.

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