An oil leak on the pavement.

How to Diagnose Car Leaking by Color and Smell

A puddle on the garage floor may be your first clue that something is wrong with your car. Indeed, car leaking can point to a significant problem, leading to an extensive repair. Before you panic, though, you need to determine what the leak represents.

Diagnosing a leak isn’t that difficult. In fact, the color of the leak or the smell it gives off will usually point to the problem. The sooner you make a determination, the better. You can use a drip pan to capture the fluid and note the color and smell of the liquid.

Here are seven visual and olfactory clues to help solve the mystery.

1. Transparent: In the Clear?

The most common car leak color is transparent or clear, although if you park on a dark surface such as a street, you may think it is something else. Fortunately, that fluid isn’t a leak at all. Instead, what you have is water condensation from the air conditioner. Reach down and touch the fluid and you’ll see it is nothing but water.

However, gasoline, like water, is also usually transparent. But various dyes and additives can change its color. The determining factor is its odor: If it smells like gasoline, then it’s gasoline. Unless you overfilled the fuel tank and the leak is a spill, the gas tank may have cracked or a fuel line may have been broken. You should consult your mechanic to find out what repairs are necessary.

2. Transmission Fluid Will Have You Seeing Red

If the fluid is red, pink or brown, then that’s a strong indication the transmission is leaking. A transmission may leak through its pan, fluid lines or broken seals. Road damage and the usual wear and tear can take its toll. Get it fixed ASAP.

3. Green, Yellow, Orange or Pink: Not Cool (but Rather, Coolant)a Chevy leaking pink coolant

Coolant, also known as antifreeze, is typically green or yellow. Certain less common colors, such as pink or orange, are also used. Use your senses to feel and smell the fluid. If it’s slimy and sweet, then you probably have a coolant leak.

4. Is Something Fishy With Your Brake Fluid?

Brake fluid is usually clear or yellow, sometimes brown if it is old. It should feel oily to the touch, but the big giveaway is its unmistakable fishy smell. A leak may indicate the master cylinder is on its way out.

5. Brown or Black: Engine Oil’s Out of Whack

Engine oil is one of the easiest fluids to detect. It smells like cooking oil, is thick and slippery to the touch and ranges in color from brown to black. Most such leaks may be attributed to a stripped oil pan drain plug — a simple repair. However, the issue could affect gaskets, seals or connections.

6. The Dirty Truth About Glass Cleaner Smell

If it smells like glass cleaner and is watery to the touch, you’re looking at windshield wiper fluid: typically blue or green, sometimes pink or orange. Whereas coolant typically drips from the front of the car, wiper fluid should fall a bit farther back in the engine compartment.

7. When Burnt Marshmallows Are Not So Sweet

Leaking power-steering fluid has the smell of burnt marshmallows and is oily to the touch. The color is usually pink or red, sometimes brown if the fluid is old. In many cases, a product to stop power-steering fluid leaks will solve the problem.

The sooner you diagnose car leaking, the more likely you are to prevent further damage. Leaking could indicate a serious issue, so it’s a good idea to consult your local NAPA AutoCare.

Check out all the chemical products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on car leaks, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Flickr.

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Matthew C. Keegan

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