Found a Puddle? Check the Colour First
You walk out to the car in the morning and there's a wet spot on the driveway. Or maybe you've noticed dark patches in your usual parking spot at work. Before you panic, take a closer look. The colour, consistency, and location of the fluid tell you almost everything you need to know.
Grab a piece of white paper or cardboard. Slide it under the drip and let it collect for a minute. Then compare what you see.
The Colour Guide
Brown or Black: Engine Oil
Dark brown or black and slippery between your fingers. That's engine oil. Fresh oil is amber or honey-coloured. As it ages and collects combustion byproducts, it darkens. If the fluid on your driveway is nearly black, the oil hasn't been changed in a while, but it's still engine oil.
Where to look: Under the front half of the car, roughly below the engine. Common sources include the oil drain plug, oil filter, valve cover gaskets, oil pan gasket, and the front or rear crankshaft seals.
Severity: Small weeps that leave a few drops aren't cause for alarm right away. A steady drip or puddle that's growing means you're losing oil at a rate that could damage the engine. Check the dipstick and top up if needed.
Reddish-Pink or Red: Transmission Fluid or Power Steering Fluid
Thin, slick, and reddish. Could be automatic transmission fluid (ATF) or power steering fluid. Many cars use the same type of fluid for both systems, so location matters here.
Transmission leak: Fluid collects toward the centre or rear of the car, under the transmission. Common leak points are the pan gasket, output shaft seal, cooler lines, and the torque converter seal.
Power steering leak: Fluid shows up toward the front, near the steering rack or pump. Lines running between the pump and rack are frequent offenders.
Severity: Transmission fluid leaks can leave you stranded if the level drops too low. The transmission overheats, slips, and eventually stops engaging gears. Power steering leaks make the wheel heavy and hard to turn. Neither is something to put off.
Green, Orange, or Pink: Coolant (Antifreeze)
Sweet-smelling and slightly slimy. Coolant comes in different colours depending on the type. Green is the traditional stuff. Orange and pink are long-life formulations. Some European cars use blue or purple. Whatever colour your coolant is, it'll feel thinner than oil and have a distinctly sweet smell.
Where to look: Anywhere under the engine bay or toward the front of the car. Radiator, radiator hoses, heater hoses, water pump, thermostat housing, and the expansion tank are all common leak spots.
Severity: Running low on coolant leads to overheating. Overheating leads to head gasket failure, warped heads, and engine damage that can write off the car. Don't ignore coolant leaks.
Clear and Watery: Air Conditioning Condensation
A puddle of clear water under the passenger side of the car, particularly on a hot day? That's almost certainly just condensation draining from the AC evaporator. Normal operation. Not a leak.
How to tell it's just AC water: It's under the passenger footwell area. It's plain water with no colour, smell, or slippery texture. And it only shows up when the AC has been running.
Light Brown and Slippery: Brake Fluid
Clear to light brown and has an oily, slightly chemical feel. Brake fluid absorbs moisture over time and darkens. A brake fluid leak is the most dangerous type of fluid leak because it directly affects your ability to stop.
Where to look: Near the wheels (caliper or wheel cylinder seals), along the brake lines under the car, or at the master cylinder under the bonnet.
Severity: Critical. If brake fluid is leaking, your braking system may fail without warning. Read our article on brake pedal going to the floor for more.
Common Engine Oil Leak Sources (By Location)
Front of Engine
- Timing cover gasket or seal: Slow seep common on higher-mileage engines.
- Front crankshaft seal: Leaks onto the serpentine belt or timing belt area. Oil flung around by the belt can make it look worse than it is.
- Oil filter or oil filter housing: Sometimes the filter isn't seated right, or the housing gasket deteriorates.
Top of Engine
- Valve cover gaskets: One of the most common oil leaks, period. The gasket between the valve cover and cylinder head hardens and shrinks over time. Oil seeps out and runs down the side of the engine. You'll often see oil residue around the spark plug wells too.
- Oil filler cap: Cracked or missing O-ring. Cheap and easy fix.
Bottom of Engine
- Oil pan gasket: The pan sits at the bottom of the engine and collects oil. Its gasket can fail, especially on cars that see rough roads or speed bumps daily.
- Drain plug: Over-tightened (stripped threads), under-tightened, or the crush washer wasn't replaced at the last oil change. Common cause of drips right after a service.
Rear of Engine
- Rear main seal: Sits between the engine and transmission. A notorious leak on many engines. Labour-intensive to replace because the transmission usually has to come out to access it.
Cost to fix common oil leaks:
- Valve cover gasket: $150 to $400 AUD / $100 to $300 USD
- Oil pan gasket: $200 to $500 AUD / $150 to $350 USD
- Drain plug or washer: $10 to $30 AUD / $5 to $20 USD (DIY)
- Rear main seal: $500 to $1,200 AUD / $400 to $900 USD (mostly labour)
- Front crank seal: $200 to $600 AUD / $150 to $450 USD
Can You Still Drive?
Depends on what's leaking and how fast.
Keep driving but monitor closely: A small oil weep that leaves a few spots. Check the oil level weekly. Top up as needed. Get it fixed when convenient.
Drive carefully, fix soon: Transmission fluid or power steering fluid seep. Keep the fluid topped up. Watch for slipping gears or heavy steering.
Do not drive: Brake fluid leak. Significant coolant leak with the temperature gauge climbing. Major oil leak where the level drops noticeably between checks.
When to See a Mechanic
Right now:
- Brake fluid leak, visible near wheels or under the bonnet
- Large puddle of any fluid forming after the car sits for a short time
- Temperature gauge climbing with visible coolant loss
This week:
- Steady drip of oil that leaves a new spot each day
- Transmission fluid or power steering fluid dropping between services
- Sweet smell from under the bonnet or near the wheels
At your next service:
- Minor oil weep that doesn't affect the level between changes
- A few drops that have been consistent for months without worsening
- AC water drip that you just want to confirm is normal
DIY Leak Detection Tips
Slide a large piece of clean cardboard under the car overnight. In the morning, check where the drip landed. Map that position to what sits above it. Front-centre is typically engine. Centre is transmission. Outer edges near wheels could be brakes, CV axles, or steering.
For stubborn leaks, UV dye kits work brilliantly. Add the dye to the fluid (oil, coolant, ATF), drive normally for a day, then scan underneath with a UV torch. The leak path glows bright green or yellow, showing you exactly where the fluid is escaping.
Ask TorqueBot
Snap a photo of the leak and describe the colour and location to TorqueBot. It can help identify the fluid type and most likely source based on your car's known weak points. Some engines are notorious for specific gasket failures, and TorqueBot knows which ones to flag for your exact make and model.