Car leaking? How to identify liquid dripping from your car and what to do

Have you ever walked up to your car and noticed there’s a mystery puddle underneath it? It’s a worrying sight and could be a sign that your vehicle has a serious mechanical problem. 

If you spot liquid leaking from your car, it's important that you do not ignore it. The puddle could be something as harmless as condensation or a sign of a coolant or oil leak. 

In this know how guide, we'll tell you how to identify what’s dripping under your car, whether it’s dangerous, and what to do about it.

What fluid is leaking from my car?

Here is a snapshot of what to do or look out for if you see fluid leaking from your car:

My car is leaking fluid – what should I do?

Liquid dripping from your car can be alarming, but it isn’t necessarily a cause for concern.  

• Make sure the leak is actually coming from your car. If there’s a puddle beneath your car and you’ve parked in a car park or on the street, the liquid could be from another vehicle
• Use a torch to look under the car to see if there’s signs of leakage. This could be a telltale shine or trail left on a component under your car
• If your vehicle is the source of the puddle, determine where the leak is coming from and what’s actually leaking. The easiest way to do that is to slide some white cardboard underneath the car while it’s parked up so it can capture the drips

These steps will give you a good idea of what liquid is actually leaking – and how concerned you should be. 

My car’s leaking clear liquid

If your car is leaking a clear, water-like liquid it’s probably just that: water. 

A clear liquid could also be a coolant leak, although this will likely have a coloured tinge to it (green, blue or yellow) and will have an odour, unlike water. See below for more information on leaking coolant. 

Car leaking water – what to do

It’s unlikely you need to do anything. Usually, leaking water is simply condensation from the aircon unit – surprisingly common during summer – or the exhaust, which is more common in winter.

Another typical cause is your windscreen washers, but again this is unlikely to be a major issue and you can probably just ignore it.

However, if you can’t identify the cause or there’s more than just a little water leaking from your vehicle, you might want to check that the clear fluid actually is water and that there isn’t a more serious issue.

My car’s leaking amber/multicoloured liquid

If you see a brownish puddle under your car that looks multicoloured when the light hits it just right - you’re probably leaking petrol or diesel.

Petrol and diesel both have very strong, distinctive scents. If you can smell something that reminds you of a petrol station, feel confident that you’ve identified your mystery puddle.

You’ll see these spills most commonly around forecourts due to careless pumping, but if they show up when you’ve parked up elsewhere, it shouldn’t be ignored.

Car leaking fuel - what to do

Do not drive your vehicle if it is leaking petrol or diesel. These fuels are highly flammable and a spark in the wrong place could set it alight. 

Fuel leaks usually occur because there’s a crack or hole in the fuel tank somewhere. As long as the fuel tank isn’t rusting away due to age, any good mechanic will be able to patch this up without having to replace the whole thing.

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My car’s leaking red fluid

Red might just be the scariest colour of any liquid to find leaking from under your car, and it usually means you have a transmission fluid leak on your hands. 

You’ll know it’s transmission fluid if there’s red fluid leaking in the middle or front of your vehicle – and it’s not only bad news for your driveway (it can stain), but it can be bad news for your car, too.

Car leaking transmission fluid – what to do

Firstly, avoid driving if you think you’ve sprung a transmission fluid leak as your car may not run properly – putting yourself and others in danger – and use could cause further damage.

It may be possible to check the transmission fluid level on your vehicle, your owner's manual should instruct you how to do this. 

Common reasons for a transmission fluid leak include:

• Broken seals
• Cracked fluid lines
• Failing gaskets
• general wear and tear

You can check the fluid levels using the dipstick (see your owner’s manual for more information on where this is), but you’ll probably need to have your car towed to your nearest garage where a professional can take a look at it. 

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My car’s leaking brown/black fluid

A puddle of amber, brown or black liquid under your car is probably engine oil, but if you want to be sure get close enough to touch it. If it feels slick and it’s hard to get off your fingers, it’s almost certainly oil.

Car leaking oil – what to do

First, try and locate the leak. It should be fairly easy to spot once you’re under the bonnet, and if the leak is from something like a valve cover gasket you may feel confident enough to fix it yourself.

If you do decide to fix it or continue driving with a small oil leak, make sure your oil tank is always filled to the appropriate level. Failing to do so could lead to lasting (and expensive) damage to your engine.

If you can’t fix the leak yourself or it’s more than just a few drips, you’ll want to check it into a local garage and let a mechanic take a look. This will help prevent the leak cause any lasting damage to your car.

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My car’s leaking red/brown fluid

A reddish-brown liquid leaking near the power steering reservoir could be power steering fluid. Unlike motor oil or transmission fluid, this’ll have a slightly sweet, burnt smell to it. 

If there’s a leak, it could be a sign there’s a problem with the hoses and tubing that carry the fluid from the pump to the steering rack, such as a loose connection or a crack. 

Car leaking power steering fluid – what to do

Firstly, check the fluid levels to see how serious the leak has become and how low you’re running.  

Although there’s nothing physically stopping you from driving with a power steering fluid leak, any sustained driving on low levels could quickly cause lasting damage so should be avoided at all costs. 

If the leak is from an easy-to-fix loose connection you can probably sort it yourself, but for anything more serious have a mechanic look at the hose and connecting parts as they may require replacing. 

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My car’s leaking a green/yellow fluid

Coolant comes in a whole host of different colours these days, meaning that if you see your car leaking green, yellow, pink, blue, red, or even clear liquid you might be facing a coolant leak. 

This might make it sound tricky to identify, but thankfully coolant has a distinctively sweet smell – think candyfloss – and an almost slimy texture, which’ll help you differentiate it from water if your coolant happens to be clear. 

Car leaking coolant – what to do

Coolant, which helps maintain the vehicle’s temperature, can leak from pretty much anywhere as there are so many coolant hoses in and around the engine. But the most common leak is from your radiator.

If your coolant’s leaking, your engine could be at risk from overheating so you need to make sure you get it seen to quickly, in order to avoid any lasting damage.

If the leak is small – from a leaky radiator cap or loose connection, you might be able to fix it yourself. However, if it’s a cracked reservoir or something else unfixable you’ll need to check it into a garage to avoid being caught out on the road.

My car’s leaking a brown fluid

The most serious leak you can have on your car is brake fluid, and if you spot a slippery, brownish liquid leaking from your vehicle you could have a problem that needs a quick response.

You’ll spot this fluid under the wheels and around the brakes in general. While brake fluid leaks are rare, if you encounter one in can be extremely dangerous.

Car leaking brake fluid – what to do

Leaking brake fluid is a huge problem because without it you won’t be able to safely control your car. So if you spot a leak don’t even try to drive your car, as you may not be able to stop.

Instead, you should find your local garage right away and get towed to a mechanic where they’ll be able to check your car over and provide the best option for fixing the brake fluid leak. If the leak happens at home, you can even call out a mobile mechanic to come to you.

Should I take my car to a garage?

If you encounter a leak that you can’t easily fix yourself, you’ll need to check your vehicle into a garage to get it seen to. 

To help you find a mechanic you can trust for any repairs that you might need, the RAC Approved Garage Network only includes garages that provide quality work and exceptional customer service, giving you peace of mind if your car needs attention. Check out the rest of our car care section for servicing, MOTs and more.

The best way to stay ahead of car issues before they develop is to get it looked at by an expert regularly.

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Is it water or oil leaking from my car?

Finding a puddle under your car can be worrying, but in many cases it's easy to tell whether you're looking at a harmless water drip or a more serious oil leak.

How to tell if it's water

Water leaking from a car is often completely normal, especially during warm weather when the air conditioning is being used. Condensation from the air-con system typically drips onto the road beneath the engine bay and forms a clear, odourless puddle.

Signs it's probably water:

• The liquid is clear and colourless
• It has no noticeable smell
• It feels like water and isn't slippery
• The puddle evaporates quickly
• The leak appears after using the air conditioning

If you place a few drops on a clean sheet of paper, water will typically dry without leaving a mark.

How to tell if it's oil

Engine oil leaks are more serious and should be investigated as soon as possible. Oil helps lubricate the engine's moving parts, and driving with low oil levels can cause severe damage.

Signs it's probably oil:

• The liquid is brown, dark brown or black
• It feels slippery or greasy
• It leaves a stain on cardboard, tarmac or paving
• It has a distinct oil or burnt-oil smell
• The puddle doesn't evaporate

Fresh engine oil may appear light brown or amber, while older oil is usually much darker.

Why is my car leaking when parked?

You may only notice a leak once your car is parked because fluids have had time to collect and drip onto the ground. While some leaks are completely normal, others could indicate a fault that needs attention.

Air-conditioning condensation

One of the most common reasons for finding a puddle under your parked car is simply condensation from the air-conditioning system. As the system removes moisture from the cabin air, water drains underneath the vehicle.

Signs it's probably air-con condensation:

• The liquid is clear and odourless
• It feels like water rather than oil
• The puddle appears after driving with the air conditioning on
• The leak is usually near the front passenger side or middle of the car

In most cases, this is perfectly normal and nothing to worry about.

Oil leaks becoming visible when parked

Engine oil can seep from worn seals, gaskets or other engine components while driving. Once the vehicle is parked, the oil collects and eventually drips onto the ground.

Common signs of an oil leak include:

• Brown, amber or black fluid
• Oily patches on the driveway
• A greasy texture
• A burning oil smell after driving
• Falling oil levels on the dipstick

Even a small oil leak should be checked, as low oil levels can lead to expensive engine damage.

Coolant system losing pressure

A coolant leak may not always be obvious while the engine is running. After the engine is switched off, pressure changes in the cooling system can allow coolant to escape through a damaged hose, radiator or seal.

Signs of a coolant leak include:

• Green, orange, yellow or pink fluid
• A sweet smell
• A low coolant warning light
• The engine running hotter than normal
• A puddle beneath the front of the car

If coolant is leaking, avoid driving long distances as overheating can cause serious engine damage.

Fuel leaks

A fuel leak can sometimes be more noticeable when the car is parked, particularly if fuel is dripping slowly from a damaged line, connection or tank.

Warning signs include:

• A strong smell of petrol or diesel
• A rainbow sheen on the fluid
• Liquid collecting near the rear of the vehicle
• Poor fuel economy

Do not drive the vehicle if you suspect a fuel leak. Fuel is highly flammable and should be inspected immediately.

Transmission fluid leaks

Vehicles with automatic transmissions can leak transmission fluid from seals, cooler lines or the transmission pan. These leaks often become visible after parking.

Signs of a transmission fluid leak include:

• Red, pink or reddish-brown fluid
• A slippery, oily texture
• Difficulty changing gear
• Delayed or jerky gear shifts

Low transmission fluid can cause costly gearbox damage, so it's important to have the problem diagnosed as soon as possible.

When should I be concerned?

A clear, odourless puddle is usually just air-conditioning condensation. However, you should arrange an inspection as soon as possible if the fluid is:

• Brown, black, red, pink, green or yellow
• Oily or greasy to the touch
• Accompanied by warning lights
• Producing a strong smell
• Forming a large puddle beneath the vehicle