Smoke and smells
Puddle under the car: how to tell which fluid is leaking
The color, smell and location of the puddle tell you what the car is losing: clear water from the A/C is normal, oil is brown or black, coolant is usually colored with a sweet smell and brake fluid is clear and oily near a wheel. A brake fluid leak means you must not drive.
Check without hurrySmoke and smells
Reviewed by Daniel Morales, founder of Reprorace SL, on
Is it serious? Can I keep driving?
Usually not urgent, but do not ignore it. It depends on the fluid. A/C water: nothing to do. Oil or coolant: you can go to a shop while watching the levels and temperature. Brake fluid or a pedal that sinks: do not drive and call for assistance. Fuel: do not start the engine and keep away from heat sources.
A careful, general answer: only someone who inspects the car can say whether it is safe to drive. When in doubt, stop somewhere safe and call for assistance.
Most likely causes
- A/C water: clear, odorless drops under the front, especially in summer.
- Engine oil: brown or black, under the engine; from the oil pan, gaskets or the filter.
- Coolant: colored (green, pink, blue or orange depending on the type) with a sweet smell.
- Brake fluid: clear or yellowish and oily, near a wheel or under the pedal.
- Transmission or power steering fluid: reddish or brown, in the middle or at the front.
Listed from more to less common in general; on your car they may be different. A fault-code reading and a check at the garage confirm which one it is.
To understand it better: How often should you run diagnostics on your car? Can I diagnose my car myself?
Car system: Engine and lubrication
What you can check yourself
Put a piece of white cardboard under the car overnight to see the color and the exact spot.
With the engine cold, check the oil, coolant and brake fluid levels.
If it smells of fuel, do not start the car and call for help.
Take photos of the puddle and the cardboard to show the shop.
Safe checks only: with the engine off and cold whenever you look under the hood, without taking anything apart and without touching hot or moving parts.
Related fault codes
This symptom is usually mechanical and does not always store a generic fault code. Even so, reading the faults of every control unit helps to rule out other problems and to reach the garage with data.
How the ECO-LITE helps diagnose it
Plugged into the OBD socket, the ECO-LITE reads the fault codes of the control units that answer, with the freeze-frame data captured when the fault happened, and shows live data on your phone or computer. With your permission, your garage can see them remotely before you bring the car in.
What to look at here: oil pressure if the car reports it, coolant temperature and level codes; a brake fluid leak does not always set a code.
Frequently asked questions
Is it normal for water to drip under the car?
Yes, if it is clear water and the A/C is on: it is condensation.
Can I drive with a small oil leak?
Yes, checking the level often and fixing it soon. If it drips onto the exhaust, it can smell burnt or smoke.
How do I know if it is brake fluid?
It is clear or amber, oily and usually shows up next to a wheel. If the level drops or the pedal feels different, do not drive.
Keep reading
- Engine and lubrication: how they work and what fails
- Car using oil: when it is normal and what to do
- Low coolant warning light on: what to do
- Soft, long or sinking brake pedal: what to do
- Car symptoms: what they mean and what to do
- Check engine light on: what to do
- How to read and clear your car's fault codes
- OBD fault codes: what each one means