Fluid is dripping from under the car – how do I know if it is dangerous?

Seeing a stain or puddle under your car can feel a little uncomfortable. “Oh no, something is broken!” doesn’t always have to be the result, but it can often be a good idea to check. At the same time, there are leaks that are important to take seriously right away. Here we go through what different drops can mean, in a simple and everyday way.

There are several fluids in a car – and they have different colors, smells, and functions. In many cases, this is completely normal, but sometimes it is a sign that something needs to be done. The very first step is therefore to try to find out what kind of fluid it is and where it comes from.

It drips clear and doesn't smell? Probably harmless

If the fluid is completely clear, has no smell, and you see it mostly when the air conditioning has been running, it's usually just condensation. This is common, especially on hot days or when the AC has been working hard, and is completely harmless.

This is the same as when water forms on a cold glass in the heat – nothing to worry about.

Colored liquid? Then you should be more attentive

If the fluid has a color or odor, it's a good idea to take a closer look, as it often involves one of the car's important fluids.

Green, yellow, pink or blue liquid is often coolant

Coolant keeps the engine at the right temperature. If it leaks, there is a risk of overheating, which can cause serious engine damage if you continue to drive. Coolant often has a slightly sweet smell.

Brown or black liquid may be engine oil

Engine oil can be light brown when new and darker when it has been used for a while. Oil leaks should always be taken seriously, as low oil levels can lead to engine damage.

Red liquid could be transmission oil

Gearbox oil or transmission fluid is often red. If it leaks, shifting can be affected and the car will start to behave differently when driving.

Strong smell of petrol or diesel?

If the fluid smells distinctly of petrol or diesel, it could be a fuel leak. This is serious because fuel is flammable and should never leak out of the car.

Brake fluid is a leak that should not be ignored

Brake fluid is often clear to slightly yellowish and can therefore be difficult to distinguish from other fluids. The problem is not what it looks like, but what it does. If brake fluid leaks, the braking system will function less effectively, making the car unsafe to drive.

If you notice fluid near the wheels or under the engine compartment, while the brake pedal feels soft or different, the car should be checked immediately.

How to research yourself: Simple tips

You don't need to be an expert to get a better picture of what's happening:

• Place a piece of cardboard or white paper under the car when it is parked. This will make it easier to see the color and amount.
• Look at where the stain ends up. If it is far in front, in the middle under the car or at the back, this may give you an indication of what kind of fluid it is.
• Smell carefully. Fuel has a distinct odor, while water and condensation are odorless.

If you are unsure, you should not continue driving, especially if it could be a problem with brakes or fuel.

Summary: When is it dangerous?

Final advice

Spotting fluid under your car doesn't necessarily mean something is seriously wrong, but it's always a sign that something needs to be checked. By looking at the color, smell, and where the drips are, you can often determine whether it's harmless or if the car needs to be checked by a repair shop.

If you are in the slightest doubt, it is always better to have a workshop look at the car in time - it can save both money and worries in the long run.

Niemi Bil has workshops in most locations where we sell cars. We carry out all types of work on most car brands and can also offer services such as tire changes, tire hotels, service, repairs, and installation of additional equipment.

Olga Granbom
Workshop Manager, Niemi Bil Spantgatan, Luleå