A Hissing Sound Coming From Your Car? Here’s What It Could Be
Photo by Anton Mishin on Unsplash
Throughout the life of your car, you may occasionally notice some unique sounds and noises as you drive. Some are typical, some are temporary, and many don’t necessarily mean that there’s a problem. There are some that are more serious than others. What if you hear a hissing sound coming from your car? Here’s what it might be.
The Four Common Causes of a Hissing Sound Coming from Your Car
- Cooling system leak
- Engine overheating
- Damaged hose or vacuum
- Exhaust leak (from the rear of the car)
- A leak in the cooling system
The main job of the coolant system, you guessed it, is to cool down the vehicle. During the combustion process, some of the energy from fuel is converted into heat. The heat is then transferred into the coolant that circulates through the engine by the water pump. The heated coolant is carried to the radiator via hoses, where it is converted to air pushed past the engine by the cooling fan. After that, the coolant is returned to the water pump and recirculated.
A cooling system has six main parts:
- The engine
- The radiator
- A water pump
- The cooling fan
- Hoses
- The thermostat
With so much going on here it makes sense that this is where multiple problems can happen. While there are a few specific causes that could create issues listed below, the entire system is often to blame for a hissing sound coming from your car.
The coolant system serves three main purposes. The first is eliminating surplus heat from the engine. The second is keeping the engine running at the temperature where it can perform the most efficiently. Lastly, it quickly gets the engine up to the proper operating temperature. A leak here can mean a few things for your vehicle and requires some additional investigation, but is a good place to start.
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The Engine Overheating
One of the more common causes that creates a hissing sound coming from your car is an overheated engine. It might be difficult to hear while the car is running, but if you turn off the car and let it idle for a few minutes and can still hear the sound, it’s generally a sign of engine overheating. Because the engine is hot if there are any fluids or liquids in the engine it will sizzle and create a hissing sound.
If you can hear a hissing sound after you turn the car off, it’s a good sign that a specific part or entire engine room is overheating. You should be able to check this with a quick look to the front of the vehicle and see a visible steam, but be careful before you touch anything as it will be very hot and potentially harmful to touch. This is a good one to leave the diagnosis and repair to the specialists.
A Damaged Hose or Vacuum
A hissing sound coming from your car could very well be from the cooling system, and one of the most vulnerable pieces of equipment in the cooling system are the hoses. These are composed of flexible rubber composites and are designed to help handle engine vibrations. You may be dealing with a vacuum leak, which means a vacuum line has been broken, especially when it’s idling. A good indicator of this is seeing your check engine light on, and your car may idle faster than usual. This also could make the vehicle run unevenly and hearing a hissing sound coming from your car could be caused by hose damage.
Hoses are made to handle high-pressure coolants, severe temperatures, oils, filth, and sludge. They can gradually deteriorate from the inside out, making it difficult to notice their damage. Hoses that deteriorate over time create small fractures, cracks, and leaks. A damaged hose might cause a fluid leak, which can cause serious problems depending on what fluid is flowing.
It could also be caused by similar damage caused by a hole in one of the car’s hoses, which will pull in air and cause noise. Under the hood, there are several hoses that distribute coolant, hydraulics, and other fluids. Hoses will deteriorate and fracture with time, and high-pressure conditions in the cracks and holes will produce hissing sounds.
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An Exhaust Leak
When your car’s system is operating properly, the gases from your engine travel to the back of the car through the exhaust and tailpipes. The muffler attached actually helps reduce the amount of noise produced in the process. The pipes help minimize harmful pollutants away from the car’s interior, and the entire system is designed to:
- Get the engine running properly and efficiently
- Help with fuel efficiency
- Reduce pollution and hazardous chemicals into the air
A hissing noise coming from your can be due to break in the exhaust manifold or pipe, or from a leaky gasket. It may be as easy as reattaching the lines, or you may require new ones. When you hear something off, stop driving as soon as it is safe to do so and wait at least 15 minutes for the engine to cool before looking more at the condition of the car.
For all of these potential issues, take a peek at the temperature gauge and see if there’s any steam coming from behind the hood before investigating. If you notice any steam and believe the engine is overheating, turn off the engine as soon as possible.
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You become accustomed to the way your car moves and the noises it produces after years of use. As a result, if you hear an unusual sound, you may be concerned and unclear whether or not your car requires repair. Your car may be alerting you to a problem based on the sound it makes. It also depends on when the noise occurs.
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