How to Tell What Fluid Is Leaking From Your Car

It is very disturbing to realize that some kind of mysterious liquid is dripping from your car. Maybe this is nothing, or maybe you have an expensive visit to the mechanic. The good news is that these stains are not that hard to decipher and tell if a fluid leak is a harmless blob or a serious problem that needs to be fixed as soon as possible. Here’s how.

When it comes to vehicle leaks, there are three things to consider: color, consistency, and location (so you can tell if a leak has occurred in the front or in the back of the vehicle). On the latter, The Car Guy says you can cover the car with newspaper or aluminum foil in the evening and then “read” the stains the next day. This way, you can determine if the leak is power steering fluid (reddish or light brown from the front of the car) or automatic transmission fluid (also often reddish or light brown, but dripping from the middle of the car).

The above infographic from Allstate is a handy guide to six common car puddles you may encounter. For example, if the blob is reddish or light brown and thin, then it is probably power steering fluid. But if it’s brown and thick, then it’s probably transmission fluid. A clear liquid can be one of two things: if it is liquid, it is probably water. But if it is smooth, then most likely brake fluid.

As Yalopnik notes, brake fluid is one of the most dangerous leaks to worry about. If you see a clear or brown smooth puddle under your car (it will feel even more slippery to the touch than engine oil or transmission fluid), don’t even try to drive it, but tow it right away. As the Art of Masculinity says :

Your vehicle’s braking system operates on a hydraulic pressure system. The brake fluid is the hydraulic fluid that maintains this pressure. Leaking brake fluid will cause a drop in pressure, which can lead to brake failure. This is not what you want when you cruise the Hill of the Dead at 60 miles per hour.

Fortunately, in most modern cars, brake fluid leaks are rare. If you have one, you will usually find it next to the wheels or in the area directly below the brake pedal.

Knowing these leaks and fixing them if necessary can help you avoid more costly repairs (such as replacing a ground gearbox). This is also what you should do before you travel .

This story was originally published on January 3, 2014 and has been updated on November 11, 19 to provide more complete and up-to-date information.


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