As a car owner, you should be ready to deal with the curveballs your car throws at you. Weird noises are one of the worst things that you can encounter. Whenever you hear something unusual from your car, you need to get it diagnosed.
What if you hear knocking sounds? Is your engine knocking at idle? There are a few reasons why this might happen. Let us look at them to get a better idea and ways on how to deal with them.
Engine knock is the knocking sound that arises in the combustion chamber of your engine. This is an audible indicator that there is something wrong with your engine.
This is one of the problems that need to be addressed immediately. The longer the problem lingers in your engine, the higher the extent of the damage.
Usually, knocking noises in your engine are caused when your engine is off sync. Every component in your engine serves a purpose. In order to get the most out of your engine, all these components need to work in sync.
Working sync will make sure that there is no energy loss when the engine operates. The timing directly affects the combustion chamber. When the ignition does not happen when it is supposed to, other problems tend to follow.
When you hear knocking noises from the engine, it could also be caused by a mechanical component that is knocking on something else.
So the timing is not the only thing you need to be worried about. The symptoms of mechanical knock are quite different from the knock caused by an engine out of sync. Even the noise is different. So you need to know exactly how to diagnose the issue.
There are 2 types of engine knocks that you need to be worried about. The first type of knock is called a detonation knock. This is the type that is coupled with an engine with bad timing.
When the detonation inside the cylinder is mistimed or doesn’t detonate at all, a detonation knock occurs.
The other type of knock is the mechanical knock. This is the knock that is caused when metal components in your engine bash against another surface. One of the well-known types of mechanical knock is rod knock.
Obviously, engine knock is not good news. But this doesn’t mean that your car is done. There are ways to solve this issue if you know what to do. Repairs can get costly. But if you notice the issue early on, and diagnose the cause properly, you could save your engine from taking a lot of damage.
There are a few different causes that you need to be educated about. Apart from the knocking, they have tended to have a few other issues as well. So when you cross-reference these symptoms, you should be able to pinpoint the exact issue with your engine.
This is the most common reason that causes engine knocking at idle. No matter how well you maintain your engine, eventually, it will wear out.
Some extent of ticking noises is actually normal. This is caused by fuel injectors. When the injectors are firing, they tend to make a ticking noise.
Fuel injectors are small electrical valves. They make a ticking or clicking sound when they open and close. But this is often masked by other noises from your engine.
The valve train often produces a clicking noise when it wears out with age. The valves, pushrods, lifters, and camshaft are the first components to suffer from wear.
Whether you are idle or driving around, these components are continuously at work. When they wear out, they do not fit as snugly as they used to. So when they move around they tend to make a knocking noise.
You do not have a lot of options when your engine is failing due to wear. You can opt to go for a complete engine rebuild. But if you do your research properly, you might find that a replacement might be cheaper. Though this is not true all the time, if you are lucky, this is a better alternative.
Unadjusted valves are another issue that causes engine knock. The knocking noises are prone to originate from the head of the engine.
This is an issue that can be solved with a simple repair procedure. So it might not be as costly as some of the other causes of engine knock.
If you remove the engine head, you will notice that the rockers are loose. Get the right set of equipment before you start. There are a special set of tools that are used to adjust valves.
This also includes a tool that will measure the space between the rocker and the valve also known as a feeler gauge. This instrument will make sure that you don’t adjust the valves and leave them too tight. This could be worse than the initial problem.
You can get this done at an automotive repair shop as well. This is a much better option. This will not take up a lot of labor, so this job is not going to blow a hole through your wallet.
As the name suggests, rod knock happens when the connecting rod in your engine comes loose and starts to knock on another surface. This happens mainly due to wear. When the bearings that hold the rod in place wear off and diminish in size, it provides room for the rod to move around. This causes rod knock.
This sound will be audible when you are driving or when you are idle. The sound is intense when you fire up the engine.
The rod makes a collision every time it hits another surface. So the longer rod knock is present the more damage is done to the engine. Every time the crankshaft rotates, a knock occurs.
With time, it will start damaging other components of the engine such as piston rings and cylinder walls. And if the problem worsens, even the crankshaft will be damaged. So this is a fatal problem that can ruin your engine.
If you identify rod knock at its early stages, then you can prevent other components from suffering damage. Even replacing the rod is a tough task. The repair costs are also high.
But if the problem lingers for a long time and damages other components of the engine, you might have to do a complete engine rebuild or an engine replacement. You can increase the lifespan of the rod with proper maintenance. But it will eventually fail.
A bad knock sensor usually causes knocks while driving, but in some cases, a bad knock sensor can be the cause for the engine knocking at idle.
The knock sensor is a part of the electrical system in modern cars. This is in charge of adjusting the air-fuel ratio, the injectors, and the timing along with some other functions. This identifies when your engine is knocking due to improper air to fuel ratio.
And accordingly, the knock sensor will adjust the mixture and eradicate the knock. But this sensor fails occasionally. When the sensor fails, it cannot feed the engine with necessary data to make adjustments when necessary.
The best way to connect engine knocking to the knock sensor is using an OBD 2 scanner. An OBD 2 scanner will scan and let you know whether the engine knock is caused by a bad knock sensor.
If your knock sensor is faulty, you need to get it replaced with a new one. After replacing the sensor, the air-fuel mixture will be automatically adjusted and you will no longer be bothered by the engine knock.
Bad faulty plugs could also result in the engine knocking at idle. Spark plugs ignite the air-fuel mixture at the ignition chamber. When one or more spark plugs fail, it will cause the engine to misfire.
Just like damaged spark plugs, loose spark plugs could also cause your engine to misfire. If you hear ticking noises, a quick inspection of the spark plugs should let you know whether it is caused by faulty spark plugs.
Spark plugs seal the combustion cylinders. So if the spark plugs can’t seal the gases in, the gas will escape causing engine knock. The same is true with loose spark plugs.
First off, engine oil protects your engine from wear. So if your engine oil is dirty, or your engine does not have enough engine oil, it will start to wear off. This will cause engine knocks. But this is not the immediate cause.
Engine oil is in charge of lubrication. It lubricates the parts inside the engine to ensure that it works smoothly. When there is not enough engine oil, these components start to grind against each other.
When metal components grind against each other, it starts to emit a squeaking or knocking noise. The noise will increase as the engine works harder.
The hydraulic valve lifter is a small cylinder that is attached to the hydraulic arm through the rocker arm. This is a common problem that a lot of vehicle owners experience. This is a well-known issue called lifter knock or lifter tick.
Lifter taps can cause a subtle ticking noise in older engines. This is quite common for engines with more than 100,000 miles under them.
This is not as problematic compared to many other problems that cause engine knock in this list. Replacing the bad lifters with new ones should solve the problem. Usually, when the lifters are addressed, the valve stems and valves are also replaced.
The entire process will cost around $500 to $1000.
As the name suggests, the timing belt is an important component when it comes to keeping the engine working in sync. The timing belt connects the camshaft and the crankshaft of the engine. Thus, it keeps the upper and lower portions of the engine in sync.
If your timing belt is broken, your entire engine will be off sync. This will cause knocking sounds to erupt from the engine. The engine will continuously misfire. If the timing belt is broken, you won’t be able to drive your car around at all.
But if the pulleys that connect the timing belt are damaged, you might be able to manage. But it is not at all recommended. Driving with a bad timing belt is not safe.
Timing belts and timing chains both serve the same purpose. Though timing chains are known to be much more durable, they too tend to break. It doesn’t matter whether your engine has a timing belt or timing chain, there is a potential threat, that it may break and cause the engine to knock at idle.
Assume that you fire up your car, and you notice that the engine is knocking. And if this is the first time you’ve noticed this, you probably won’t know the exact cause. So, without a proper diagnosis, you need to make a decision.
So, can you continue your journey, or do you need to cancel the trip and get the knock fixed before you take your car down the road?
When you do not know the exact reason for the knock, driving is not a good idea. Some of the causes mentioned above have serious repercussions. And more often than not, if your engine is knocking at idle, it will probably get worse when you drive.
Driving a car with engine knocks makes you prone to run into an accident. Some causes like rod knock and a bad timing belt can cause the car to go out of control. And driving your car will further aggravate the problem which could cause havoc.
Even if the problem might not be so threatening, driving a car engine knock will surely damage the engine. As more components start to give out inside your engine, you will need to go through a complete engine rebuild.
If you want to protect your engine from further damage, you should not drive a car with an engine knocking at idle.
Usually, when the engine knocks, the check engine light in your dash will start to blink. A blinking check engine light says that you should not drive your car any further.
The exact way to deal with an engine knock depends on the cause itself. Before thinking about ways to fix engine knock, first, you need to find out what is causing the engine knock.
Almost all the causes mentioned above have other unique symptoms apart from the engine knock. So, if you can notice any other symptoms along with engine knock, you should be able to narrow down the suspects. And some problems can be figured out using a physical inspection.
Once you identify the cause, you can take your next step. Depending on your skillset and the tools available, you can either decide to do the repairs yourself or hire a mechanic.
You can easily handle problems like a bad set of spark plugs or engine oil that needs to be replaced.
But other than that, the rest of the causes that cause engine knock are quite complicated to repair. If the repair procedure seems complicated, it is better to hire a professional. Especially because the work is done on the engine.
By attempting complicated repairs yourself, you could further damage the engine. This is why you should allow someone with experience and the right set of tools to work on your engine.
The exact cost to repair an engine that is knocking at idle drastically varies depending on the cause of the knock. If the knock is caused by a faulty spark plug, the repair will only cost around $50. If it is caused by rod knock or a bad timing belt, repair costs could be as high as $4000 or more.
Here are some of the most common questions regarding engine knocking at idle.
Fuel quality is measured by octane. Most manufacturers mention the minimum required fuel octane level for their cars. When the fuel octane is below the recommended octane level, engine knocks happen, but it does not happen at idle.
Fuel octane level only matters when the engine is working hard. At idle the engine will not require high-quality fuel. But fuel octane is one of the primary causes of engine knocks in luxury and performance cars. This is because they require fuel with high octane, and owners tend to neglect the requirements of the engine.
Timing chains last a lot longer than timing belts. But due to the beneficial properties of timing belts, modern cars tend to use timing belts over timing chains. Timing belts can last anywhere from 60,000 miles to 100,000 miles.
There is no way to exactly predict the exact cost to repair a knocking engine. The repair cost directly depends on the cause of the knocking. Depending on the failed components repairs could cost as low as $50 or as high as $4000.
First, you need to correctly identify whether the sound you are hearing is a knock or a faint tick. Engine making ticking sounds are quite normal. This is due to the fuel injectors. The valves in the fuel injectors open and close.
During this motion, they make a ticking noise. So it is normal to hear the ticking noise of the fuel injectors. In some models, this sound is loud enough to hear it. In most cars, this is masked by the sound of the engine.
Engine oil with high viscosity will temporarily solve some causes of engine knock. High viscous engine oil can provide better lubrication for your engine. If the knocks are caused by the lack of lubrication, then this might work.
But even if it works, this is not a permanent solution. You need to address the cause properly as soon as possible.
The longer your engine knocks, the more damage it takes. So, even if your car is idle, a knocking engine will cause excessive damage if you hear knocking sounds.
Even if your engine is not knocking at idle, you should not leave your car idle for long. Idling as little as 2 minutes could be equivalent to burning fuel that can be used to drive a mile. It not only wastes gas but also your battery.
You will be wasting your charge with no means of recharging. This will cause your battery to drain and hinder the use of electronics in your car.
Engine knock is one of the worst things that you can face as a car owner. Engine knocks are indicators that there is something wrong with your engine. More often than not, engine knocks will lead to more engine damage if left unchecked.
There can be many reasons why your engine is knocking at idle. If your engine is knocking at idle, it will only get worse when you drive. Whether you are driving or not, engine knock can slowly cause severe damage to your engine.
Due to the sheer number of possible causes, fixing engine knock is not as straightforward as many other repairs. You need to diagnose the issue and find exactly why your engine is knocking. Then you need to seek help from a professional to work on your engine.
If you can’t diagnose the issue yourself and you continuously hear engine knock, you need to immediately get your car diagnosed by a certified mechanic.
