So, you pull out of your parking space at the mall or your garage, and you notice this where you were parked:

fluid leak

Your reaction?

freak out

…but I say to you:

don't panic

First, you must ascertain which fluid it is. Then, you must determine whether or not this is something that needs to be addressed like yesterday. The major thing that will factor into this sense of urgency, is how big a puddle it is, and which fluid it is.

This post is to help you determine which type of fluid leaks you are seeing.

First up, engine oil.

porsche leak

Engine oil starts off being a golden brown, but as it picks up deposits from inside your engine and begins breaking down, it will become more and more black in color. Oil leaks are one of the most common leaks, and when it becomes a large enough leak to leave a puddle like this, it should be addressed very quickly. This Porsche has its engine in the rear of the vehicle, otherwise an oil leak won’t be noticed back here.

If your engine gets too low on oil, severe damage can occur. Check the level immediately and fill as needed, then get the vehicle to your local auto mechanic.

Next up, automatic transmission fluid (ATF).

transmission fluid

As depicted above, new transmission fluid is a very bright red and as time goes on it too begins to break down and becomes more and more brown in color. This fluid, along with the next on our list, is one of the easiest fluids to identify due to its color. It has a distinctive smell, but there’s no way I can put a smell like this into words. As it gets more and more brown, it begins to have a burned smell.

If the fluid in your transmission gets low, you’ll know it because the car will act like a slipping clutch in a manually shifted vehicle. The engine will rev up, but the car won’t move. Check your dipstick to see what conditions should be met before you check it. In most cases they want the engine warm and idling, vehicle in park. Fill as needed (a little bit goes a long way), and swing by your local garage.

Next, brake fluid.

brake fluid leak

This will usually be near one of the wheels, due to a leaking brake hose/line, caliper piston (disc brakes), or a wheel cylinder (drum brakes). Brake fluid starts out almost clear/amberish and has a distinct smell (sort of like fish oil). Similar to other fluids, it changes colors as it becomes contaminated and will become very dark.

If you see a leak, like this one pictured, DO NOT DRIVE THE VEHICLE! This means the pressurized brake system has been compromised and the brakes will likely not stop the vehicle (you’ll notice the brake pedal goes to the floor). Get the vehicle towed to your local auto mechanic.

Next we’ve got some power steering fluid.

ps fluid leak

This one can be a bit tougher to decipher between it and brake fluid, as they share similar traits. They each have their own smell, but similar in color: fairly clear/amberish. The difference here, is that power steering fluid will almost always be directly under the engine when it leaks, because it’s either the power steering pump, rack & pinion, or one of the lines that are leaking, and these are all situated towards the front/center of the engine.

You’ll know your power steering fluid is low by the sound your pump will make. It will whine, and if it gets low enough, the power steering won’t have any power. It’ll be difficult to turn the steering wheel. Top off as needed and have it inspected.

Easiest one to spot of them all? Coolant/antifreeze.

antifreeze leak

I can’t generalize here by saying that’s always green, but in old vehicles it is. GM dabbled with Dexcool (puke) in the early 00’s before discovering that this orange stuff was junk, Chrysler/Toyota now have a bright pink coolant, and BMW has a blue coolant (brilliance in engineering here, think washer fluid). Go ahead and facepalm. I just did. Most “global” or “universal” coolants are yellow.

At any rate, this leak will almost always be near the front of the vehicle. The only case I can think of where it wouldn’t be, is with vehicles that have rear heater cores (conversion vans, large SUVs, minivans). Pipes or hoses run the length of the vehicle that supply the rear heater core with coolant.

There are a TON of places you can spring a coolant leak from, but the major ones are heater core, radiator, water pump, radiator hose(s), heater hose(s), thermostat housing, timing cover, head gasket. If it’s a large leak, tow it. Otherwise, fill it and run it by your shop to have a pressure test performed.

Here’s an easy one, washer fluid.

washer leak

Easy unless you happen to drive a newer BMW. Most washer fluid, except your deicer types, are blue in color (just like the coolant in newer BMWs). Some of the deicer ones are purple, and other are orange. If you see this leaking, shrug your shoulders and carry on going wherever it is you were off to before you noticed the puddle.

Typically this leak is caused by a frozen/broken washer fluid reservoir, or a broken feed hose. Not a huge deal, just get it checked at your convenience.

Last, and the least of your worries.

puddle

Yup. Water. H2O. The most abundant resource on our planet. Are you one of those people that always leave your car’s HVAC (heating ventilation air conditioning) modes on floor/defrost? Defrost engages the car’s AC system which dries out the air coming into the passenger compartment. Is it summer time and you’re running the AC?

This is condensation drainage from a properly operating AC system and is completely normal. If it didn’t drip onto the ground it would back up and spill onto your car’s carpet inside the vehicle and give you a musty smell. This is a good puddle to see and you should not be alarmed at all.

Being informed about what you’re seeing will better serve you so you can explain to your trusted service advisor what it is you saw and how big a problem it is.