The Telltale Signs: How to Identify Automotive Fluid Leaks

Fluid leaks are often one of the first signs of car trouble. Left unaddressed for too long, fluid leaks can lead to serious problems ranging from braking and steering issues to total engine failure—which is why leaks should always be repaired as soon as possible. Knowing how to identify a fluid leak and the type of fluid that’s leaking is a useful skill for any driver. To help you do this, we’ve compiled a list of some of the most common and important fluids you might encounter and how to tell which is which.

How to Identify Automotive Fluids

The easiest way to identify which type of fluid is leaking from your vehicle is to look at the color and consistency of the fluid.

Red Fluid

There are two types of red fluids that are commonly used in vehicles: automatic transmission fluid and power steering fluid. However, some vehicles use automatic transmission fluid instead of power steering fluid for their power steering systems.

Fresh power steering fluid starts off red in color, but as the fluid ages and deteriorates, it transforms from red to reddish brown and eventually becomes regular brown. At this point, it may be challenging to distinguish from other fluids based on color, but you can check the consistency and odor. If it’s power steering fluid, it will have a thin, oily consistency and a slightly sweet, burnt aroma that’s similar to burnt marshmallows.

Automatic transmission fluid also starts as a vibrant red fluid when it’s new, but it will gradually become a reddish or orangish-brown shade as it ages. Unlike power steering fluid, automatic transmission fluid has a notably slick texture and a petroleum-like smell.

Light Yellow Fluid

If you notice a light yellow fluid underneath your vehicle, it’s probably brake fluid. This is a serious safety concern; without enough brake fluid in the system, your brakes may not work. Avoid driving and schedule an appointment immediately.

As brake fluid ages or becomes contaminated, its color will darken. In cases where the brakes haven’t been properly maintained, the fluid may become dark brown. If the fluid is from the brakes, it will have an oily, slippery texture and smell similar to fish oil.

Pink, Yellow, Green, or Orange Fluid

Coolant, also known as antifreeze, comes in a variety of colors: pink, yellow, and green. It also has a slimy texture and a distinctively sweet smell. If you notice the fluid under your car appears orange, you likely have rust accumulating in your cooling system. A properly functioning cooling system is vital to the health of your engine, so fluid leaks or signs of contaminated fluid should always be addressed as soon as possible.

Blue Fluid

Windshield wiper fluid is the only blue fluid used in vehicles, however, depending on the formulation it can also be purple, green, orange, or pink. You can confirm that it’s wiper fluid by checking the consistency, which will be thin and watery, with an odor that’s similar to an ordinary household cleaner. Avoid using your windshield wipers until you can have the reservoir or the lines repaired.

Brown and Black Fluid

Engine oil starts off as a light amber or light brown hue and gradually darkens each time it circulates through the engine. Eventually, it becomes a dark brown to black color. It’s easy to recognize it because of its thick, slippery texture and petroleum odor. If you’re only seeing small drops of oil, you can keep the engine oil topped off until you’re able to bring your car in for an inspection. However, significant leaks should always be addressed immediately to prevent engine damage.

Clear Fluid

When it comes to clear fluid leaks under your car, there are two possibilities: water and gasoline. If you notice water, it’s generally nothing to be concerned about. In many cases, it’s caused by condensation draining from the air conditioner. If the fluid is gasoline, it should be easy to recognize because of its smell. Unlike water, gasoline leaks pose serious safety concerns and should be treated with the utmost caution. Avoid driving your car until you’re able to have it thoroughly inspected by a qualified auto repair shop.

Visit RPM Automotive Services for All Your Automotive Needs

Hopefully, this has given you a better understanding of the various fluids in your vehicle and how to identify them. To assess the severity of a leak, we recommend placing a large piece of cardboard under your car overnight and examining it the following morning. The quantity, color, and location of the leak can help us diagnose the issue quicker.

At RPM Automotive Services, we specialize in comprehensive repairs and maintenance services for imports and domestic vehicles. We’re a member of the ASCCA, and our entire team is ASE-certified. Whether you're dealing with a fluid leak or need engine repairs, you can trust our team to provide professional, friendly service and high-quality workmanship. Contact us today at (707) 800-4586 or schedule an appointment online.

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