How To Identify That Leak Under Your Car By Its Color

Your car is leaking, and you don't know if it's safe to drive or not. You aren't even sure which fluid is leaking. Generally speaking, figuring out which fluid is responsible for the spots on your driveway requires the process of elimination. Read more to learn how you can identify the fluid that's leaking from your car (and what you should do about it).

This will give you the most important information: the color. Once you know that, use the following guide to identify the leak:

GREEN: Suspect The Antifreeze (Coolant)

If the fluid is green, it's antifreeze. At one point, antifreeze was always green, but now you have to be aware that it can also be bright orange, blue, or pink. If you touch the fluid, it will feel sticky and thick, and it smells sweet.

If you let the antifreeze run out of your car, your engine is going to overheat, and leave you stranded somewhere. If the leak is small (a few spots), you can add antifreeze and drive for short distances, until you can get the problem fixed. If the leak is large, don't drive it, or you'll burn up your engine.

If it's the middle of winter and the leak is tiny, don't give into the temptation to ignore the leak and keep adding antifreeze. Antifreeze is poisonous, even in small amounts, and its sweet taste and aroma is attractive to animals. You don't want to accidentally poison your dog because you've put off getting a small antifreeze leak fixed.

CLEAR-TO-LIGHT BROWN: Suspect The Brake Fluid

Brake fluid is clear-to-brown and slick. Brake fluid leaks usually show near the wheels of your car, or directly below the spot the brake pedal sits. 

Your brakes work on a closed hydraulic system, and a leak will cause a drop in the pressure in your brakes, which can send you skidding when you should be stopping.

Fortunately, people often mistake water condensation in warm weather for brake fluid, so suspect that first if the fluid is clear. Touch the fluid, and rub it between your fingers. Brake fluid will feel very slick and slippery between your fingers.

If it's water, you're safe. If it's brake fluid, don't drive your car any further. Have it towed to the mechanics office.

PALE YELLOW OR REDDISH-BROWN: Suspect The Power Steering Fluid

If the fluid is light reddish-brown or yellow and thin, it's probably your power steering. You can usually tell that there is some loss of hydraulic pressure in the steering system, because your car wheel is going to take more muscle to turn. 

To check, pop your hood to find the reservoir for the power steering fluid. If it's low, you know that you have a leak. However, you can usually manage a slow leak for a while by just topping up the fluid levels every week until you can afford to get the repairs done.


How dark your oil looks is usually determined by how diligent you are about changing it. The more relaxed you are about your oil changes, the darker your oil is going to be. 

Oil leaks are probably the most common causes of spots under a car and can range from negligible (if annoying, because they stain,) to worrisome. In an older car, it's not uncommon to need to check the oil weekly, topping off as needed.

If your car is leaking oil steadily, and you find yourself looking at bigger and bigger spots on the garage floor, make an appointment with a mechanic as soon as you can afford it.

RED: Suspect Your Transmission Fluid

New transmission fluid is light red and darkens as it ages. 

Transmission fluid is the lubricant that lets you shift your gears correctly and cools down your transmission. If you let your car get too low on transmission fluid, you will burn up your transmission, grind your gears to halt, and really damage your car. Often you'll have other warning signs, aside from the leak, that your transmission is in need of repair because you'll feel the car slipping or jerking in and out of gear.

If the leak is very tiny, you can check the transmission fluid level to make sure that it hasn't gotten too low, and then take it to the mechanic's for repair. If the fluid is low, or the leak is significant, you want to have your car towed in for repair. at a transmission shop.

It's never fun to find spots on your driveway floor where your car was parked. If you don't know what those spots are from, it can be nerve-wracking. By evaluating the color of the fluid leaking from your car, you can make an educated decision about how to proceed.