Car Leaking Fluid: Causes and How to Identify The Liquid

If your car leaks any liquid, you should fix the problem as soon as possible. But the fact that something is dripping under your car does not always mean that something is wrong. Read on!

Car Leaking Fluid

It’s everyone’s worst nightmare. You head to the car in the morning and find a puddle of fluid underneath. Not only does it take most people by surprise, but it can also cause some fear.

After all, how much is the repair going to cost you? Before you get too worked up, it’s important to determine what fluid is leaking because not all of them will require a major car repair.

Let’s look at the seven most common car fluid leaks and what you can do about them. 

7 Common Fluids To Leak From A Car

The most common fluids leaking from a car are coolant and motor oil. In many cases, it may not be a leak at all you see, but water condensation dripping from the air conditioner. This is completely normal.

Any fluid coming from your vehicle should be investigated more closely, but not all of them mean something is wrong. Let’s take an in-depth look at these seven common leaking car fluids.

1. Antifreeze Leak

Coolant Leaking E1609789888621

Coolant or antifreeze is needed to regulate engine temperature. When the engine gets too hot, you might notice a puddle of coolant below the car.

Interestingly, it is one of the most common car fluid leaks. It could also indicate that there is a defect with the cooling system. If you notice coolant below the car, you want to have it checked out.

Typically, antifreeze is a bright color, making it difficult to miss. You will also know this by the smell because antifreeze has a distinct sweet odor. It would either be green, pink or orange. Make sure the pets stay away from it because it is highly toxic. 

Hopefully, the leaking antifreeze is only caused by a loose clamp or hose, but it could mean a broken water pump or other serious coolant system concern. 

RELATED: How to Fix a Coolant Leak

2. Motor Oil Leak

Leaking Oil

As you drive, it’s possible for some oil to seep out of the engine, especially if you’ve put a lot of miles on the motor. However, if you notice oil under the vehicle after it has been parked, you want to have it looked at. Driving with not enough oil or a lack of pressure can cause major engine damage.

Motor oil color depends on when you last changed it. It could be amber or light yellow if you recently performed a tune-up or it could be black or darkish brown if the oil is old.

Most of the time, oil leaks are caused by engine seals or gaskets that have gone bad. It could also be due to a defective oil pan or improperly installed oil filter. Either way, a professional should take a look. 

RELATED: 8 Best Oil Stop Leak Additives

3. Transmission Fluid Leak

Car Oil Leak

Transmission fluid is often mistaken for oil, but you should be able to tell the difference because of the red tint. However, old transmission fluid can appear brown instead.

Just like with engine oil, these leaks are serious and should always be looked at. You might notice the puddle anywhere under the transmission or from the lines going to the cooling system. 

RELATED: 6 Causes of Transmission Fluid Leaks

4. Fuel Leak

Car Fuel Leak E1609793222449

It doesn’t matter whether you have a gas- or diesel-powered vehicle; leaks can occur. If you notice a leak near the rear of the vehicle, you must consider a defective fuel tank is the cause. With that said, fuel can also leak near the front of the car if a fuel injector is going bad or fuel line has broken. 

Both fuels are clear, but diesel might have a slight blue tint to it. The way to determine it is gasoline is by the smell. Gas has a distinct smell, even after sitting for some time. 

Fuel-related mechanical problems aren’t just annoying but also dangerous. You don’t want to drive a vehicle with this combustible fuel leaking. 

5. Brake Fluid Leak

Car Fluid Leak

Hydraulic brake fluid is used in every modern vehicle. Without the proper amount of fluid, the brakes can’t operate correctly. That’s why you need to have any leaks looked at immediately.

Brake fluid appears yellow and oily or brown if it is older. The key component of this fluid is the slick feel. It will be very slippery. You can also check the reservoir to see if the levels are down. 

RELATED: 5 Symptoms of a Brake Fluid Leak

6. Windshield Washer Fluid Leak

Washer Fluid

Sometimes the windshield washer reservoir succumbs to the heat from neighboring systems and cracks. When this happens, you might notice a leak under the car that is blue and has the consistency of water.

Another clear sign is that the reservoir is empty even though you haven’t used the fluid. If the crack is bad enough, you will see it pouring out as you fill the container. 

7. Water Leak

Water Dripping Under Car

Of all the fluids that might be leaking, water is the least concerning, especially if you have been running the air conditioner. Excess moisture causes condensation, which can drip from underneath your vehicle.

However, if you start to notice an abundance of water dripping, it doesn’t hurt to have it looked at. 

Diagnose Common Car Fluid Leaks

Diagnosing common car fluid leaks isn’t difficult if you are observant. Follow these steps to determine what is leaking.

Place a piece of cardboard under the leaking area of the vehicle.

Examine the color of the leaking fluid. Here is a basic cheat sheet of common fluid leaks.

  • Green, Pink or Orange: Antifreeze
  • Amber or Dark Brown/Black: Motor Oil
  • Red: Transmission Fluid
  • Clear/Blue-tinted: Fuel
  • Yellow: Brake Fluid
  • Blue: Windshield Washer Fluid
  • Clear: Water

You can also smell the fluid to see if it is recognizable. Several of the substances listed above have a unique smell. For example, antifreeze always smells sweet, while gasoline smells like a fuel pump. If your car is leaking oil, it could smell like burnt rubber. Additionally, transmission fluid also has a sweet smell, but it is tarter than coolant. 

Learning how to identify these common car fluid leaks is essential to maintaining a reliable ride. Some leaks can be discovered and repaired at home, but others require a professional. It never hurts to have your mechanic look at any leak you are experiencing. 

Remember, driving a vehicle with any major leak can lead to more disastrous consequences, whether it affects your on-road safety or leads to more expensive repairs down the road.

Magnus Sellén
Written by:

Magnus is the owner and main author of Mechanicbase. He has been working as a car mechanic for over 10 years, and the majority of them specialized in advanced car diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.

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