You must have noticed certain sounds or noises in the engine of your car while starting it and driving in your daily routine. While most of these sounds are normal and come due to the functioning of different running components of the engine, some of these could indicate a potential malfunction or a problem.
The engine and other parts are made of different metals that expand at high temperatures, due to combustion occurring in the engine. When you turn off the engine, the temperature settles, and these parts contract, creating a specific type of noise. This sound is absolutely normal and occurs in almost all vehicles.
But if you notice your car making noise after the engine is turned off, there could be something wrong with one of the many engine components and you should get it checked and fixed, to avoid any complex issues. Let’s go over some of the most common reasons behind a car making noise after turning off the engine, and how to fix them;
Noise Coming from the Engine after Turning It Off – Most Common Reasons
You should suspect the following problems if your engine makes noise after turning off;
1 – Damaged Head gasket
Head gasket is one of the most important components of the engine and keeps the coolant from escaping or mixing with the oil. It bears the grunt of the temperature and stress constantly over time and gets damaged if not replaced on time.
If your car is making noise after the engine is turned off, you should suspect a damaged head gasket and get it checked for cracks or leaks.
2 – Insufficient Coolant
Coolant is the most important part of the radiator and is the main media that regulates the temperature of the engine. Over time, the level of coolant can get low or even due to a leak in the pipes or radiator.
Low coolant with leaks in the assembly lets the air into the system and can create noise due to insufficient functionality. It can also damage the critical parts of the engine and should be quickly inspected in case you hear noises in your car after it’s turned off.
3 – Low Level of Oil
A low level of oil is the most common reason behind your car making strange noises when turned off, particularly knocking sounds. When the engine oil level is low, it cannot lubricate the moving parts properly inside the engine, which then rub against each other.
This can increase the friction and over time, leads to knocking sounds in the engine, even after turning it off. You should routinely check your oil level to avoid this issue.
4 – Problematic Battery
If you’ve not serviced your battery lately or replaced it since buying the car, it is highly likely that it is running low on juice and cannot provide adequate voltage to the components.
When the engine is turned off, a draining battery cannot adequately supply power to the components, and these appliances stop working abruptly. This can also produce a strange cracking noise when you turn off the car. Replacing the battery can get rid of this issue easily, and at an economical cost.
5 – Damaged Hoses
Different parts of the engine are connected via different relays and hoses. When these hoses get damaged or cracked due to wear, it can lead to leakage of fluid and air into the system.
This can also present as crackling noise when you turn off the engine and it can become fatal if the issue is not diagnosed and repaired on time. You should get your engine checked by an expert technician at priority.
6 – Blocked Exhaust System
The exhaust system ensures that the gases and unburnt fuel are emitted outside properly via the catalytic converter and muffler tip. If the exhaust system is clogged due to debris or sludge, it can lead to poor and slow passage of gases.
This can result in wheezing noises and even small blasting sounds if the unburnt carbon catches a spark. You should get the exhaust serviced regularly to prevent this problem.
7 – Loose Hanging Components
If the engine components or mounts get loose over time, they can rattle when the engine is turned off and lasts for a few seconds. This can be alarming and troublesome if these parts are not checked timely. These parts can even damage the other engine components if not fixed and could prove fatal.
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How to Fix it?
It is crucial that you get your car checked immediately when you hear noises after turning off the engine. It could be as simple as the radiator fan moving or simple contraction of the engine part, or as fatal as a damaged head gasket or leaking hoses.
1. Replace the Head Gasket – Repairing a head gasket is a complex job that usually doesn’t get rid of the issue. It is ideal to get the gasket replaced with a new OEM part for satisfactory results.
2. Fix the Leaking Radiator – You could simply top up the coolant in the radiator but if there’s a leak, it is important to fix it first to solve the issue.
3. Replace your Battery – Replacing an old worn out battery is the best way to fix this issue, and dry batteries are usually more reliable.
4. Check all the Hoses – Check all the hoses for cracks and damages, and get them replaced by an expert technician.
5. Service the Exhaust System – Simply using an exhaust system cleaner can unclog the whole exhaust assembly and enhance the car’s performance, apart from getting rid of any weird noises.
One should be wary of any kind of strange noises coming from the car, even after turning off the engine. Although these noises could be just normal metal sounds but can also indicate a serious problem underneath the hood.
Taking your car to an expert technician for expert diagnosis and repairs is crucial so that you can get rid of the issue and prolong the service life of your car.