What is leaking from under my car?
If you find drops of liquid or, worse, a large puddle near your car, you will undoubtedly want to know what is leaking and how bad it is. You don't necessarily need to call a tow truck right away. You can first find out for yourself what the liquid is and what you need to do about it.
First of all, you need to find the lea. Park your car on a level surface and place a sheet of paper, newspaper, cardboard, or aluminum foil under it to catch the leak, as it will be difficult to see on dark asphalt. Next, collect the fluid — and this is where your high school chemistry lessons will finally come in handy.
Find the leak
First, you need to determine where the leak is coming from. If you have a rear-wheel drive car, which is typical for most older Soviet cars, then a leak from the rear is most likely related to the differential fluid. But it could also be coming from the fuel tank.
Several types of fluids can leak from the engine compartment. One of them is brake fluid. It often leaks from the rear of the engine compartment, where the master brake cylinder is located, or along the brake lines. Power steering fluid and coolant are more likely to leak from the front of the engine compartment. Oil can leak from anywhere in the engine compartment, but most often leaks from the oil pan at the bottom of the engine itself. Windshield washer fluid usually leaks around the fluid reservoir, which may be located in different places in the engine compartment, depending on your car model.
The transmission is usually located behind the engine, so a leak at the rear of the engine compartment or slightly behind it may be related to transmission fluid. Water dripping from the air conditioner evaporator also collects somewhere around the middle of the car. By the way, there is no need to worry about it.
What color is the leaking fluid?
Let's start with a visual identification. Different fluids in a car have distinct colors, which can help you identify the source of the leak.
Brown or black fluid
This may indicate engine oil, which is brown in color but turns black over time.
Pink, red, or brown fluid leak
Power steering fluid and transmission fluid are pink or red, but can turn brown over time.
Clear, yellow, or brown fluid leak
Brake fluid is initially clear or yellow, then it turns brown.
Yellow, green, pink, or orange fluids
Coolant is usually yellow or green. However, some are pink or orange. You can check the color of the coolant in the coolant reservoir. NB: Do not open the reservoir cap when the engine is hot!
Blue or green
Windshield washer fluid is usually blue or green, but it can also be pink, orange, and many other colors.
Clear fluid leak
Gasoline itself is clear, although some additives and dyes can color it other colors.
What does the leaking fluid look like?
The next thing you can do is use your sense of touch. For example, rub the fluid between your fingers. Its consistency will help you identify it. NB: it is best to do this while wearing rubber gloves.
Oily fluid leak
If you have ever changed the engine oil in your own car, you have an idea of its consistency. It is oily. Transmission fluid and power steering fluid are also oily, but more liquid than engine oil. Differential fluid, on the other hand, can be thicker than engine oil.
Something viscous and sticky
This indicates brake fluid or coolant.
Liquid and watery
This is most likely gasoline or windshield washer fluid. Fortunately, these fluids have distinctive odors. And here we smoothly transition to smell
What does the leaking fluid smell like?
Some automotive fluids have a distinct odor that can be used to identify them.
Gasoline smell
It is difficult to find a car owner who is not familiar with the characteristic, sharp, and persistent smell of gasoline. Therefore, there are usually no problems with identifying it. Transmission fluid is petroleum-based, so it may also smell slightly like gasoline.
Oil smell
Motor oil has a sweet or grassy smell.
Fish oil smell
Brake fluid may smell slightly fishy.
Sweet smell
This is most likely coolant.
NB: Antifreeze also tastes sweet. But you should never test this yourself, for which antifreeze is toxic. This is why it is important to clean up leaks. The sweet smell can attract wild or stray animals, for which antifreeze is toxic. For the same reason, keep coolant containers away from children.
Slightly oily or sweet/ethereal smell
This is the smell of power steering fluid. The smell depends on its composition. If the fluid is mineral oil-based, it smells like oil. If it is ether-based, it has a sweetish chemical smell.
Windshield washer fluid smell
This one is simple. Windshield washer fluid smells like household glass cleaner. And vice versa.
You still don't understand where the leak is coming from
If you've touched and smelled everything, but it still isn't clear, pay attention to other symptoms and changes in the car's performance. For example, an oil leak can cause a smell of smoke in the cabin. If you are having problems with steering, it could be a power steering fluid leak. And malfunctions in the automatic transmission may indicate a transmission fluid leak.
If you have fluid samples in your garage or trunk, such as leftover engine oil after an oil change or windshield washer fluid, you can compare them to the leaking fluid.
You've found a leak, now what?
Your next step will depend on the type of leak.
Brake fluid leak
If you have a brake fluid leak, it is extremely dangerous to drive your car. Take it to a service station or fix the problem yourself. A brake fluid leak may require replacement of the brake cylinders or brake lines.
Gasoline leak
A gasoline leak is most likely coming from a hole in the gas tank, but it can also be coming from the fuel pump or fuel lines. If the leak is severe, it is best not to continue driving and to call a tow truck. If you want to locate the leak yourself, disconnect the battery terminal before jacking up the car.
Power steering fluid leak
To fix a power steering fluid leak, you may need to replace the steering rack or power steering pump. Therefore, the only option here is to take the car to a service center.
Coolant leak
This can lead to overheating, which can further damage the car. Therefore, the size of the leak must be taken into account. If the coolant level is not dropping too quickly, you can continue driving. And, if possible, buy the appropriate type of fluid at the nearest gas station to top up as it leaks.
Transmission fluid leak
Low differential fluid or transmission fluid levels can cause wear on the gears inside these parts, so again, it is very important to maintain sufficient fluid levels. The most likely cause of a differential fluid leak is wear on the differential cover. A transmission fluid leak may indicate a problem with the transmission fluid pan. These parts are relatively easy to replace.
Water leak
Water drips from the air conditioner evaporator. Cold refrigerant in the air conditioning system causes water to condense on the outside of the air conditioner's evaporator. This is not a malfunction.
Water droplets from the exhaust pipe may be the result of water vapor condensing in cold weather. Small puddles left behind are also a normal process.