By Bob Lacivita | Updated: February 10, 2023

Leaking car fluid can be a cause for concern, especially if you notice something other than water. This guide will help you identify the fluid leaking from your car, focusing on the color, texture, and location of the leakage.

Identifying the Cause of the Leak

Car fluid leaks are not uncommon, and it’s crucial to address them promptly, particularly if the fluid is gasoline or brake fluid. The first step in solving the issue is determining the type of fluid causing the leak.

If the fluid is water, there are common and harmless reasons for its presence under a parked car. Water condensation from the air conditioning system and exhaust condensation are typical sources.

However, if it’s not water, you’ll need to identify which of the seven other car fluids it might be, helping you decide whether it’s a do-it-yourself (DIY) fix or if professional service is required.

Fluid Color Coding and Texture

Different car fluids have distinct colors, textures, and smells. Here’s a quick guide to help you identify the leaking fluid based on its characteristics:

  1. Coolant or Anti-freeze:
    • Color: Bright green or orange, pink, blue, or yellow.
    • Texture: Slimy with a sweet smell.
    • Check: Radiator hoses, coolant reservoir, and radiator.
  2. Engine Oil:
    • Color: Yellowish (new oil) to light brown to black.
    • Texture: Slick to the touch.
    • Check: Oil pan drain plug, oil filter or gasket, and spilled oil on the frame.
  3. Gasoline:
    • Color: Clear and thin, with a pungent odor.
    • Check: Fuel hoses, lines, fuel filter connections, and gas tank.
  4. Brake Fluid:
    • Color: Clear (when new) to yellow to light brown.
    • Texture: Slick and oily with a strong bitter/sour odor.
    • Check: Brake fluid hydraulic system.
  5. Transmission Fluid:
    • Color: Light red/pinkish (when new) to dark brown.
    • Texture: Oily but thinner than engine oil, with a heavy petroleum odor.
    • Check: Transmission pan gasket, cooler lines, or external seal.
  6. Power Steering Fluid:
    • Color: Reddish or light brown (when new) to dark brown/black.
    • Texture: Motor oil-like but thinner.
    • Check: Power steering high-pressure line or fluid reservoir.
  7. Windshield Wiper Fluid:
    • Color: Blue, green, or orange, with the consistency of water.
    • Check: Reservoir for cracks, fluid lines/hoses for leaks.
  8. Water:
    • Clear, odorless, feels like water.
    • Check: Air conditioning condensation, exhaust system condensation, sunroof drains.

Stop-Leak Additives

For minor leaks, aftermarket sealant additives can be added to oil, transmission fluid, and the radiator. These additives, when used correctly, can temporarily stop minor leaks by swelling O-rings and gaskets. However, caution is advised not to overuse these additives.

Conclusion: Addressing Car Fluid Leaks

Even a small leak can be indicative of a more significant problem. With this information, you can better assess whether the leak is something you can fix yourself or if it requires professional attention. Remember that any fluid leaking from a car should be addressed promptly to avoid potential complications.