Identifying Car Fluid Leaks: What’s Draining from Your Vehicle?

Do you have a mystery leak coming from your vehicle? This article will help you with identifying car fluid leaks. But be aware that in most cases, this is just the first step. Once you have a suspect or two in mind, it’s vital to schedule an appointment with your mechanic to confirm your suspicions and repair the leak.

car fluid stain on the floor

Image by Hans from Pixabay

Why It’s Important to Tell Your Mechanic About Fluid Leaks and Their Colours

Accurately describing a leak from your car or truck can shorten the time it takes your mechanic to diagnose the problem. It gives them a starting point for investigation, which saves them time and may well save you money too.

When you tell your mechanic about a leak, be sure to share the following information:

  • The appearance of the leak, including its colour
  • When and where you notice the leak
  • If you see fluid all the time or only sporadically
  • Any other symptoms that seem to coincide with the leak

Concurrent vehicle problems related to leaks might be difficulty steering, noisy brakes, or trouble shifting gears.

As you’ll read below, the location and appearance of the leak are important clues to share with your garage. If possible, take a photo or video of the leak or active dripping from the bottom of the automobile, especially if fluid is lost occasionally but not all the time.

Identifying Car Fluid Leaks: Common Culprits

Engine oil

Appearance: amber, dark brown, or black (often shiny and may have a burnt smell)

Location: beneath the vehicle’s engine

Causes: faulty seal or gasket in the engine, worn valve cover or oil pan, or improper oil change process, resulting in a loose oil filter or oil pan plug

You can check your oil level yourself if you know how, or you can ask a full-service gas station to assist you. If you replace oil and find the level drops soon after, you likely have a leak. You might also get a low oil pressure light illuminated on your dashboard.

Never run your car on low oil, as this can damage the engine or cause a breakdown.

Radiator fluid

Appearance: often lime green but may also be bright orange or pink, with a watery consistency and a sweet smell (but a bitter flavour to deter animals from licking it)

Location: beneath the front end of the car or truck

Causes: many possible, including a loose hose clamp, faulty heater, broken water pump, or a worn or malfunctioning radiator

Radiator fluid is either pure antifreeze or coolant, which is antifreeze mixed with water. The former protects your engine in cold weather, while the latter works to prevent overheating (but also gives winter protection). Talk to your mechanic about what’s best for your vehicle. Meanwhile, don’t drive with a radiator leak, or your vehicle may not start in winter or could break down in summer.

Brake fluid

Appearance: yellow (new) to brown (older) and extremely slippery

Location: beneath the reservoir (check owner’s manual) or around wheels

Causes: a leak in the brake fluid reservoir or a worn seal or conduit in the brake system

Losing brake fluid can cause a catastrophic brake failure. Therefore, if you believe your vehicle is leaking brake fluid, stop driving and have it towed to your mechanic.

Transmission fluid

Appearance: similar to engine oil but usually more red in colour and may smell like gasoline

Location: beneath the centre of the vehicle

Causes: multiple possibilities, including a faulty gasket or O-ring, worn transmission line (from heat and abrasion), cracked torque pump, or compromised axle seal

Drive as little as possible if you believe you have a transmission leak, as you could lose transmission functionality. If the leak is large or if you are experiencing difficulty changing gears, have the vehicle towed to your mechanic’s shop.

Power steering fluid

Appearance: may be clear or reddish (new) or brown (old) and similar to engine oil but thinner in consistency

Location: under the front left side of the vehicle where the steering column is located

Causes: a leak in the power steering fluid reservoir, cracked or loose hose, worn seal on steering pump, or excess pressure in the power steering system that blows out the seals

Please note that if you have a purely electric power steering system, your vehicle does not use power steering fluid, so your leak would be caused by something else.

Losing power steering fluid can cause your car’s or truck’s steering mechanism to fail suddenly, which is extremely dangerous. It’s best to get a tow to your mechanic and not drive under these circumstances. [Read more about Power Steering Fluid Leaks From Our Gary’s Blog]


Appearance: pale brown and iridescent, with a strong, unmistakable petroleum odour

Location: usually beneath the gas tank but may be elsewhere under the vehicle, including multiple puddles

Causes: worn fuel line, faulty fuel injector, malfunctioning fuel pressure regulator, or damaged fuel tank, including after tampering related to fuel theft

Obviously, leaking gas from your vehicle can cost you money. But this is also a serious fire and explosion hazard you want to avoid. Don’t drive, and have the vehicle towed for repair.

Washer fluid

Appearance: usually bright blue and the consistency of water

Location: beneath the front of the vehicle or towards the back if there is a rear wiper

Causes: hole in fluid reservoir, open reservoir cap, loose or worn line to front wipers, or worn or loose line to a rear wiper

Your front reservoir also serves your rear wiper. However, some vehicles have a separate holder for headlamp wipers, which will be detailed in your owner’s manual.

While leaking washer fluid won’t affect your vehicle’s drivability, it can make it difficult to see properly, so you should take care of it. This may be one leak you can fix yourself if the cap to the fluid reservoir wasn’t fastened properly or you see a loose connection to your wipers. Otherwise, it’s usually an easy job for your mechanic to do.


Appearance: clear

Location: beneath the front of the vehicle or below the exhaust pipe(s)

Causes: dripping from air conditioning condensation or a byproduct of engine combustion

Unless you notice a lot of water or the leak coincides with operational issues, this shouldn’t be a worry. Small amounts of water from the AC and tailpipe are normal.

Don’t Ignore Fluid Leaks from a Car, Truck, or Van

A leak in your vehicle is nearly always the warning sign of a problem. Not only do you want to prevent accidents and breakdowns by addressing leaks right away, but you also don’t want small problems to morph into bigger, more expensive ones. An experienced mechanic can figure out what’s happening and repair it so you can drive safely and with confidence.