Identify the fluid by color, feel and location
Coolant, also called antifreeze, is usually bright green, orange, pink or yellow, feels watery and slightly slippery, and has a sweet smell. It drips from near the front of the car, under the radiator or engine. Transmission fluid is typically red or pink when fresh, turning brown as it ages, and feels oily. It tends to drip from the middle or front of the car.
Brake fluid is clear to light yellow or brown, feels slick, and is often found near a wheel or under the master cylinder near the driver side. Power steering fluid can look like transmission fluid. Motor oil is amber to black and drips under the engine. Knowing which fluid it is helps you clean it, and tells your mechanic what is leaking.
Coolant first: pets and kids
Coolant is the urgent one. Ethylene glycol coolant is poisonous and tastes sweet, which can attract dogs and cats. A puddle on a driveway or garage floor should be cleaned right away, not left for a weekend wash. Keep pets inside or away until it is gone.
Cover the puddle with absorbent such as kitty litter, let it soak up the liquid, sweep it into a bag, and dispose of it according to local hazardous waste guidance. Then wash the spot with water and detergent and rinse, keeping the rinse water contained. If you think a pet has licked coolant, contact a veterinarian immediately. Our guide to pressure washing around pets covers keeping animals safe during cleaning more generally.
Cleaning the stain on concrete
Coolant is water-based and usually comes up relatively easily once absorbed. A detergent wash and a stiff brush handle fresh spots. Older spots can leave a faint colored ring because of the dye, which often fades further with repeat cleaning and sun.
Transmission and power steering fluid are oily and behave like motor oil. Absorb, then apply a concrete degreaser, let it dwell, scrub and rinse. Brake fluid is not oil-based and can actually damage some paint and coatings, so be careful on painted or epoxy-coated garage floors. Absorb it, wash with detergent and rinse well. On bare concrete, it rarely leaves a lasting stain if cleaned promptly.
Why these stains spread
A slow leak drips in one spot, but tires roll through it and carry it toward the street. Rain and sprinkler water spread it wider, and the dye or oil soaks into pores as it goes. That is why a small leak turns into a long streak over a few months. Hot summer concrete also helps oily fluids sink in faster.
Fix the leak. No cleaning method keeps up with a car that drips every night. A drip pan or mat under the car until it is repaired keeps the driveway from collecting more.
A sheet of white cardboard under the car overnight is an easy way to confirm what is leaking and where. The color and position of the spot on the cardboard tell you more than a stain on gray concrete, and it is useful to show your mechanic.
Keep it out of the storm drain
Automotive fluids are exactly what storm drain rules aim to keep out of creeks and the ocean. Los Angeles Municipal Code section 64.70.02 prohibits discharging untreated wash water from paved-surface washing into the storm drain system. Absorb first, wash second, and contain or redirect rinse water so it does not run down the gutter.
Used absorbent goes in a sealed bag, not loose in a yard bin where pets can reach it. Check your local household hazardous waste guidance for how to dispose of fluid-soaked material and leftover fluids.
Realistic results and when to call a pro
Fresh spills clean up well. Old transmission fluid stains behave like old oil stains: they lighten significantly but can leave a shadow. Dye rings from coolant usually fade. If the whole driveway is spotted from years of different leaks, a full clean with stain pre-treatment gives a more even result than chasing each spot. As of October 2026, driveway cleaning is $0.50 per square foot on our instant quote calculator, with a $195 minimum. Say Wash It pre-treats fluid stains by type before cleaning the full surface.
Key points
Identify the fluid by color, feel and location
Coolant, also called antifreeze, is usually bright green, orange, pink or yellow, feels watery and slightly slippery, and has a sweet smell. It drips from near the front of the car, under the radiator or engine. Transmission fluid is typically red or pink when fresh, turning brown as it ages, and feels oily. It tends to drip from the middle or front of the car.
Coolant first: pets and kids
Coolant is the urgent one. Ethylene glycol coolant is poisonous and tastes sweet, which can attract dogs and cats. A puddle on a driveway or garage floor should be cleaned right away, not left for a weekend wash. Keep pets inside or away until it is gone.