Cars can leak all manner of different fluids, and most mean your vehicle needs attention. Whether it’s fixing an oil leak, a coolant leak, a transmission leak, a brake fluid leak, or any other type of vehicle leak, all should be treated as a priority. Read our guide for the low down.
Car leaks: they can take a variety of different forms and they’re never a good sign.
But they can give you a heads up that something's wrong with your vehicle.
You’re almost certain to encounter one, some, or all of the following leaks at some point in your motoring life.
If you spot one, you should take steps to resolve any underlying issues as soon as possible.
Doing so will help ensure your vehicle remains safe and roadworthy, and could save you from even bigger repair bills later on.
Acting quickly on any leak you spot will help you avoid the stress of breaking down (and the cost, if you don’t have breakdown cover).
What’s a worst-case scenario?
Here’s an example of how a relatively cheap fix could prevent a huge repair bill or even having to scrap your car.
A minor coolant leak might be caused by a loose clamp or a worn hose. It could cost £50-£150 to repair. If ignored, however, it might lead to your engine overheating. If this happens, it could result in a blown head gasket or a warped cylinder head, either of which could lead to damage that would cost thousands of pounds to fix.
Undertaking a coolant leak repair promptly would have prevented this unpleasant outcome.
Look out for these car leaks…
1. Engine oil leak
What are the signs of an engine oil leak?
- Dark brown or black puddles underneath your car
- The smell of burning oil
- Low oil level on the dipstick
Causes: Worn gaskets, oil pan damage, or valve cover leaks
Tip: Check under the engine and around seals for oil seal leakage. Top up and get oil leaks repaired promptly. Stopping oil leaks from the engine as soon as you spot them should be a top priority.
NB: Seal oil leaks are fairly common, especially in older vehicles or those with high mileage.
2. Coolant leak / antifreeze leak
What are the signs of a coolant leak / antifreeze leak?
- Bright green, pink, or orange fluid under the car
- Sweet smell
- An overheating engine or warning light
Causes of leaking coolant: Radiator, hoses, water pump, or gasket issues
Tip: Inspect your hoses, radiator, and expansion tank. Never drive with low coolant. Undertake coolant leak repairs as soon as possible.
3. Transmission fluid leak
What are the signs of a transmission fluid leak?
- Red or brown fluid under the gearbox area
- Slipping gears or rough shifting
Causes: Worn seals, pan damage, or cracked lines
Tip: Check under the car and on transmission housing; address leaks promptly to avoid (costly) gearbox damage.
4. Brake fluid leak
What are the signs of a brake fluid leak?
- Clear to yellowish fluid near wheels or under car
- Soft or spongy brake pedal
- Warning light on dashboard
Causes: Brake lines, callipers, or master cylinder leaks.
Tip: Brake fluid is critical for the safety of you, your passengers, and other road users so stop driving immediately if a brake fluid leak is suspected.
5. Power steering fluid leak
What are the signs of a power steering fluid leak?
- Red, pink, or amber fluid under front of car
- Whining noise when steering
- Hard steering
Causes: Hoses, pump seals, or rack leaks
Tip: Check the reservoir and hoses regularly.
6. Fuel leak
What are the signs of a fuel leak?
- Smell of petrol/diesel around car
- Wet spots under fuel tank
- Decreased fuel efficiency
Causes: Fuel lines, injectors, or tank damage
Tip: Fuel leaks are dangerous. Fix immediately to prevent fire risk.
7. Windshield washer fluid leak
What are the signs of a windshield washer fluid leak?
- Blue fluid puddles under car
- Washer reservoir empties quickly
- Washer spray weak
Causes: Cracked reservoir, hose damage, or loose connections
Tip: Usually minor but easy to fix before winter or rainy weather.
8. Differential or axle fluid leak (for AWD/4WD cars)
What are the signs of a differential or axle fluid leak?
- Thick dark fluid under rear axle or wheel hub
- Unusual whining noise while driving
Causes: Worn seals or gaskets on differential housing
Tip: Check fluid levels at service intervals (as specified by the manufacturer in the manual) as low fluid can damage gears.
9. Air conditioning / refrigerant leak
What are the signs of an air conditioning/refrigerant leak?
- Clear or oily residue around AC lines or compressor
- Weak cold airflow
- Hissing sound when AC running
Causes: Hose cracks, seal failure, or condenser leaks
Tip: Check lines visually and feel for moisture. Refrigerant leaks reduce efficiency but won’t usually cause a breakdown immediately.
General tips to spot leaks early
- Visual inspection: Look under the car and around engine bays regularly
- Smell test: Sweet (coolant), petrol, or burnt oil smells can indicate leaks
- Check your fluid levels: Dipsticks and reservoirs help catch drops before they become critical
- Look for stains on driveways or garages
Bottom line:
Stopping car oil leaks, coolant leaks, transmission fluid leaks, or any other type of leak early prevents breakdowns, costly repairs, and crucially, safety hazards. Even a small puddle can indicate something serious brewing under your car.
