What’s Leaking? Deciphering the Puddle under Your Car

By: StaffAugust 31, 20212 min

If you’re dealing with a car leak, you may not know if you need to drive straight to the mechanic or ignore the problem altogether. Don’t fret. There are plenty of indicators you can see for yourself that can help you determine your best course of action. When you find a leak under your car, soak it up with a paper towel to get a better look at its color, smell and texture.

Use the following list to match up your puddle’s characteristics with its identification so that you’ll be able to diagnose your car’s leaks.

Clear and watery: This is probably just condensation that forms and drips after your air conditioner has been on. No need to worry about this any further.
Dark brown or black, gassy smell, oily texture: Regular engine oil is most likely the culprit in this case. If it’s motor oil, the pavement directly under your car’s engine oil pan should be stained, leaving a dark residue. While this could be caused by something as simple as excess oil spilling out from your last oil change, it could also be something more serious that would need attention from a professional. Check your oil level. If it’s at an unsafe level, if the gassy smell is particularly strong or if the leaking persists, take your car to a mechanic.
Reddish-brown, sharp and unfamiliar odor, greasy texture: This could be transmission fluid, especially if it’s located near the middle of your car’s underside, sits on top of the surface and soaks in slowly. Have your mechanic look at the problem as soon as possible to be safe.
Yellow to clear, dull scent, slick consistency: Your brake fluid is leaking. This is not something you want to mess around with or delay inspection on. Service your car immediately.
Green, pink, yellow or blue; sweet smell; tacky feel: Your puddle is probably caused by a coolant (antifreeze) leak in this case. This is the second most common leak and can lead to your engine overheating. This substance is also known to be deadly to animals, so until you get this checked out, keep any pets away from the car.
Blue, orange or green; slight sweet smell; thin consistency:
Most likely, you have a windshield washer fluid leak. This is not something that needs immediate care. Black, thick texture: In rear-wheel drive vehicles, this could indicate a rear differential leak. Your puddle might be forming under the rear axle of your car, which could mean that your differential seal is faulty. The ability to identify even these few basic liquids could save you a lot of worry—and your driveway or garage a lot of stain damage. When it comes to figuring out what’s leaking from your car, remember that if you’re not sure, the next best thing to do is to take your car in and have a professional help you out in diagnosing the problem.