Why Is My Car Leaking & What Could It Be?
- Diagnostic
FixMyCar discusses why your car might be leaking and what you can do to fix it.
Book a leak repair nowEllie Dyer-Brown
Tuesday September 24 2024
10 min read
Cars rely on various fluids to function, from engine oil to coolant, so when you spot a puddle of unknown liquid near your vehicle, it can set alarm bells ringing. Try not to assume the worst - instead, follow the advice in this guide to identify the source of the leak and find out whether it needs to be repaired.
Contents
What to do if your car is leaking
My car is leaking clear liquid
My car is leaking multi-coloured liquid
My car is leaking amber or brown fluid
My car is leaking reddish brown liquid
My car is leaking blue, yellow, green or pink liquid
What to do if your car is leaking
The first thing to do is check whether fluid is definitely leaking from your car or if it is coming from another vehicle parked nearby. Grab a torch and look under the car to see if you can spot where the fluid is coming from.
Next, find a piece of cardboard and slide it under the leaking area. Leave it until you’ve collected enough of the fluid to determine what it is - you can usually identify car fluids by their smell and colour.
My car is leaking clear liquid
A clear liquid is likely water, which isn’t a cause for concern. If there is a slight colour to the fluid, it could be coolant. Keep reading for more information on coolant leaks.
Why is my car leaking water & what can I do about it?
Usually, leaking water comes from condensation in the aircon unit in summer and the exhaust pipe in winter (which can cause white smoke from the exhaust, as we discuss here). You don’t need to do anything to prevent this, as it is a part of the normal functioning of your car.
My car is leaking red fluid
Whether from a human or a car, leaking red fluid is a universally bad sign. The most likely cause is a transmission fluid leak, especially if the liquid is coming from the front of your car. Be careful when investigating this one, as it can stain.
Why is my car leaking transmission fluid & what can I do about it?
Transmission fluid is responsible for lubricating your vehicle’s transmission system, which is a pretty essential job. Leaks happen due to wear and tear and should never be ignored.
Components that could be to blame include:
Worn seals and gaskets
Corroded transmission lines
Cracked pan gasket
Leaking torque converter
In addition to a puddle of red fluid, you may also notice the check engine light appear, a burnt smell while driving, a slipping or rough transmission, and a humming sound.
You can check the level of your transmission fluid using a dipstick - take a look at this guide for more information about how to check various fluid levels or consult your owner’s manual. The next step is to get your car towed to a garage for a repair. You should never drive with a transmission fluid leak.
Chances are, you won’t be able to pinpoint the exact source of the leak without help from an expert.
My car is leaking multi coloured liquid
Fuel - whether petrol or diesel - looks like an iridescent amber-coloured liquid that is shiny and multicoloured in certain lights. If you’ve spotted leaking fuel, it will be accompanied by a strong and distinctive scent; you’ll recognise the smell from filling up at a garage forecourt.
Why is my car leaking fuel & what can I do about it?
A crack in the fuel tank often causes fuel leaks, which can happen due to corrosion and rust or damage from an accident. As long as the tank isn’t excessively corroded, it should be easy for a mechanic to patch up the leak without needing a replacement.
Other components that could be to blame include:
Faulty fuel pump
Damaged fuel lines
My car is leaking amber or brown fluid
Dark brown fluid is most likely dirty engine oil, which appears as an amber-coloured liquid when clean. You can tell whether the fluid is engine oil by its texture - it will be greasy and hard to get rid of when you dip your finger in it.
Why is my car leaking oil & what can I do about it?
Engine oil leaks are common, particularly in older cars. They happen when components become corroded, making them more susceptible to wear and liable to leak.
Numerous components could be to blame for an oil leak, including worn-out seals, degraded engine gaskets, a damaged oil pan and many more. Providing the leak is minor, you should be able to top the oil up to an appropriate level and drive the vehicle to a garage to be repaired.
Alternatively, small leaks may be repairable by using a stop leak additive or high-mileage oil blend. It’s worth noting that accumulated oil can cause further damage to engine components, increasing the corrosion rate, so the best long-term option is to book a proper repair.
My car is leaking reddish brown liquid
A liquid that is reddish brown is likely power steering fluid. It is used in the power steering system to make a hydraulic link between the front wheels and steering wheels. Without it, steering your car would be much more difficult.
You can tell power steering fluid apart from transmission fluid because it should have a slightly burnt, sweet smell.
Why is my car leaking power steering fluid & what can I do about it?
There is probably a leak in the network of hoses and tubes responsible for carrying fluid between the pump and steering rack caused by a loose connection or crack.
It’s not a good idea to drive for too long with a power steering leak. The first thing to do is check the reservoir level - this will tell you how serious the leak is and whether you can continue driving to make it to a garage.
A simple loose connection should be easy enough to fix on the driveway, but a mechanic should repair anything more serious.
My car is leaking blue, yellow, green or pink liquid
Coolant comes in a wide range of colours, so if you’ve noticed a bright red, yellow, green or pink puddle under your car, it’s the most likely culprit. The best way to make sure is to get close to the liquid and smell it - coolant has a very sweet, candyfloss scent and often a slimy texture.
Other signs your car is leaking coolant include:
A sweet smell in and around the engine compartment
Coolant warning light
Low coolant
Why is my car leaking coolant & what can I do about it?
As with most leaks, coolant leaks are usually caused by corrosion. You may have a blown radiator hose, worn pump, faulty header tank cap, cracked radiator or leaking seals.
If the leak is small and slow, you may be able to repair it yourself or top up your coolant and drive to a local garage for a repair. However, you should never drive with very little or no coolant in the system, as this could cause severe (and expensive) engine damage.
My car is leaking brown fluid
By far, the worst fluid leak you could encounter is brake fluid. Leaks of this type are rare, but that doesn’t mean you should discard the possibility entirely.
You will find leaking brake fluid in slippery brown puddles around the brakes and wheels - if this description matches the kind of leak you’re experiencing, do not drive under any circumstances.
Why is my car leaking brake fluid & what can I do about it?
The most common cause of leaking brake fluid is a worn seal in the calliper, wheel cylinder or master cylinder. Find out more about brake components and how they work here.
The reason you shouldn’t drive with a brake fluid leak is that you may not be able to slow or stop when you press the brake pedal. Instead, call your breakdown provider if you have one to tow you to a garage.
This kind of problem requires attention from a mechanic as soon as possible. Here are five other brake problems you shouldn't ignore.
Should I take my car to a garage if it’s leaking?
Most motorists don’t have the skills and knowledge required to fix leaks. Some minor problems may be solvable by watching 'how-to' videos, but for the most part, the safest option is to take your car to a garage - or call a mobile mechanic - for professional advice.
Fortunately, you’re in the right place. FixMyCar has the UK’s largest network of independent garages and mobile mechanics to help you get back on the road faster.
Frequently asked questions
What causes oil leaks in cars?
There are several places where an oil leak may occur, such as:
Oil pump gasket
Oil filter gasket
Oil pan
Drain plug
Seals
Most leaks are caused by corrosion and general wear. Over time, parts stop working as effectively and become more susceptible to leaks. High pressure and heat can lead to cracks, and some components may work themselves loose. All of these things can result in engine oil seeping into places it shouldn’t be.
What is the most common leak in a car?
The most common type of fluid leak is engine oil, followed by coolant, while the most serious leak is brake fluid.
Can you drive a car with a leak?
The answer to this question is, somewhat frustratingly, that it depends. If you have a small engine oil or coolant leak, you should be able to drive a short distance to a garage after you have topped it up to get it repaired.
You should never drive if the leak is:
Fuel
Brake fluid
Transmission fluid
Ideally, you should get all leaks fixed as soon as possible and avoid driving until the repair is complete.
Are car leaks expensive to fix?
The cost of repairing a car leak varies significantly depending on the type of leak, location and the work needed to patch it up. On average, car leak repairs cost £81.98 when booked through FixMyCar.
Below is a table of the average costs for different car manufacturers.
| Car make | Average price |
|---|---|
| Audi | £70.10 |
| BMW | £76.25 |
| Citroen | £69.89 |
| Ford | £77.42 |
| MINI | £115.99 |
| Mercedes | £81.58 |
| Nissan | £131.02 |
| Peugeot | £92.69 |
| Renault | £94.65 |
| Toyota | £110.50 |
| Vauxhall | £74.01 |
| Volkswagen | £73.35 |
| Volvo | £85.40 |
However, if any major components need replacing - like the head gasket - the repair will be considerably more expensive.
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