Riding mower engine knocking. 9 Fixes For When Your Lawn Mower Won’t Start

Lawn Mower Makes Loud Clicking Sound

If you’re like most people, the sound of a lawn mower brings to mind memories of summertime childhoods spent playing in the backyard.

But if you’re unlucky enough to own one of those old-fashioned mowers that makes a loud clicking sound, you know it can be pretty annoying.

In this blog post, we’ll take a look at the reasons why lawn mower makes loud clicking sound and how to fix it. Read on!

• Lawn Mower Makes Loud Clicking Sound- Causes
• 1. Low Battery Voltage
• 2. Clutch Problems
• 3. Blades Hitting a Foreign Object
• 4. Faulty Solenoid
• 5. Faulty Starter
• 6. Faulty Flywheel
• Lawn Mower Making Rattling Noise
• 1. Faulty Bearings
• 2. Faulty Exhaust
• 3. Loose Head Bolts
• 4. Dirty Air Filter
• FAQs- Lawn Mower Makes Loud Clicking Sound
• What Does a Clicking Solenoid Mean?
• Why Does My Lawn Mower Sound Like a Helicopter?
• How Do I Stop a Lawn Mower from Clicking?
• Author

Lawn Mower Makes Loud Clicking Sound- Causes

Low Battery Voltage

One possible cause of the loud clicking noise on your lawn mower could be low battery voltage. When the battery is weak, it might not provide enough power to the motor, which can cause it to click loudly. Try charging the battery or replacing it with a new one to see if that fixes the problem.

Clutch Problems

Another common cause of lawn mower clicking noise is a loose clutch. The clutch works with the transmission to engage and disengage the blades while you mow, and it can become loose over time.

You might think that a clutch problem would result in your lawn mower not running, but that’s not always the case: if it becomes too loose, the clutch will slip and make a loud clicking noise. The good news is that the clutch is relatively easy to replace.

Blades Hitting a Foreign Object

It’s also possible for blades of grass, sticks, rocks, or other objects to get caught between the blades while you mow, eventually causing them to stop moving properly. The blades might make that loud clicking noise while you mow if this happens.

If the blades are hitting something, they’ll usually slow down or stop completely after a while. The best thing to do is stop the mower and check underneath it for anything that might be in the way.

Once you remove whatever is stuck, the blades should normally work again.

Faulty Solenoid

The solenoid is a part that can fail and cause the lawn mower to make a loud clicking noise. The solenoid essentially acts as a switch, allowing current to flow through it and to the starter motor.

If your solenoid is damaged or defective in any way, it could be making a loud clicking noise when the lawn mower is running. Try checking it for loose wiring or debris that might have gotten stuck in it, and replace it with a new one if necessary.

Faulty Starter

If the starter is faulty, it might not provide enough power to the engine, which can cause the lawn mower to click loudly. Try replacing the starter with a new one to see if that fixes the problem.

Faulty Flywheel

The flywheel is another part that can make the mower click loudly. It works with the starter to turn over the engine, and if it fails or becomes damaged, you could hear a loud clicking noise when the mower is running. Try checking for debris that might have gotten stuck in it, and replace the flywheel if necessary.

Lawn Mower Making Rattling Noise

If your lawn mower is making a rattling noise, several possible causes are. Here is a look at some of the most common ones:

Faulty Bearings

The bearings in your lawn mower can also make a rattling noise, which will result in the lawn mower not running. If the bearings get too hot, they could warp and start rattling while the mower runs.

This is a common issue in mowers left out in the rain, but it can also occur under normal operating conditions. If this happens to you, replace the bearings.

Faulty Exhaust

Another common problem that can cause a lawn mower to rattle while running is a loose or damaged exhaust.

The exhaust pipe attaches to the engine, and vents used combustion gases out of the mower. If it becomes loose or is damaged in some way, you’ll hear a rattling noise when you run the mower.

Loose Head Bolts

The head bolts of your engine are another potential cause of a rattling noise while your lawn mower is running. The head bolts hold the engine’s cylinder head in place, so if they become loose, you’ll hear a clattering noise coming from the engine.

This is an issue that’s common in mowers that have been through accidents or have had their engines rebuilt, but it can also occur in perfectly normal situations. If the head bolts become loose, you’ll need to tighten them before your lawn mower runs properly.

Dirty Air Filter

A dirty air filter can also cause a lawn mower to make a rattling noise while running. This can occur in two ways.

• First, the engine will be hard to run if the filter becomes dirty enough to restrict airflow
• Second, if the filter is worn out and no longer properly filters out particles, you’ll hear a rattling noise coming from the engine compartment

If your lawn mower is making a rattling noise, the best thing that you can do is clean or replace the air filter. If the problem persists after replacing the filter, it might be time to get your engine’s head bolts checked or replace your exhaust.

FAQs- Lawn Mower Makes Loud Clicking Sound

What Does a Clicking Solenoid Mean?

A clicking solenoid means one of two things. Either the starter has become faulty, or there is something stuck in between the blades of the mower.

If the sound is made only when the mower is turned on, your starter is most likely faulty. A new starter can be easily installed by yourself or a repair shop.

Why Does My Lawn Mower Sound Like a Helicopter?

If your lawnmower sounds like a helicopter when you turn it on, the blades are likely hitting something and need to be adjusted.

Loosen the bolts on top of the mower deck with a wrench and blade screwdriver2. Carefully lift up the mower housing and turn the blades until they are even3. Tighten the bolts securely and replace the housing

How Do I Stop a Lawn Mower from Clicking?

If your mower is making an intermittent clicking noise, it could be due to debris stuck in the blade or starter.

Turn off the mower and remove the spark plug wire2. Rotate the blades by hand and check for any objects that may be stuck in between the blades3. If you find something, remove it and turn on the mower to see if the noise has stopped

If your lawn mower is making a rattling noise, it will need to be fixed before you can use it again.

In most cases, this simply means replacing the air filter, but if this does not resolve the noise issue, you may need to have your engine’s head bolts checked or replace your exhaust.

Author

Hi, I’m Ricky. I’ve been involved in lawn care and landscaping from when I was 15. To be honest, I didn’t like the idea of pushing mowers, collecting grass clippings, and maintaining flowerbeds at the time. But having seem the passion my parents had for gardening and outdoors and the effort they put in maintaining the health and beauty of our landscape, I couldn’t help but not only admire their hard work but also I became a part of it. As someone who loves to spend time with nature’s best, I find myself learning a lot more about gardening and outdoors on a daily basis. Not to mention I love to share the knowledge I’ve gathered over the years with my readers at We Mow Dallas. To be clear, I don’t have a Master’s degree in gardening or anything like that. Everything I’ve learned about gardening, landscaping, and lawn care spring from passion and engagement with my parents. And with a ton of free information out there, plus the ability to run tests and determine what works best for lawn care and landscaping, every day is an opportunity to learn and implement something new. My goal with We Mow Dallas is to teach you exactly how to maintain your lawn and landscape. And since I walk the talk in reality, you shouldn’t hesitate to join me in this wonderful world of landscaping and lawn care. View all posts

There are a number of reasons, mechanical and otherwise, why a mower won’t run. The good news is that fixing most all of the issues is easy enough for a DIYer to handle.

By Tony Carrick and Manasa Reddigari | Updated Aug 8, 2022 4:03 PM

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Lawn care can be tedious, but once the grass starts growing in the spring, mowing becomes a fact of life in most neighborhoods. When you finally muster the strength to tackle that first cut of the season, there are few sounds as disheartening as that of a lawn mower engine that turns over but doesn’t start.

Before you drag the mower in for repairs or invest in costly replacement parts, first make sure that a clogged air filter, soiled spark plug, damaged safety cable, clogged mowing deck, or contaminated gas isn’t to blame. Work through the following steps, and you may be able to get your puttering grass guzzler up and running again in no time.

A lawn mower repair professional can help. Get free, no-commitment repair estimates from pros near you.

Change the lawn mower carburetor filter.

Your lawn mower’s air filter guards the carburetor and engine from debris like grass clippings and dirt. When the air filter becomes clogged or too dirty, it can prevent the engine from starting. To keep this from happening, replace paper filters—or clean or replace foam filters—after every 25 hours of engine use.

The process for removing the filter depends on whether you are operating a riding or walk-behind lawn mower. For a riding mower, turn off the engine and engage the parking brake; for a walk-behind mower, pull the spark plug wire from the plug. Then, lift the filter from its housing.

The only choice for paper filters is replacement. If you’re cleaning a foam filter, wash it in a solution of hot water and detergent to loosen grime. Allow it to dry completely, and then wipe fresh motor oil over the filter, replace it in its housing, and power up the mower—this time to the pleasant whirring of an engine in tip-top condition.

Check the spark plug.

Is your lawn mower still being stubborn? The culprit may be the spark plug, which is responsible for creating the spark that ignites the fuel in the engine. If it’s loosened, disconnected, or coated in water or carbon residue, the spark plug may be the cause of your machine’s malfunction.

Locate the spark plug, often found on the front of the mower, and disconnect the spark plug wire, revealing the plug beneath. Use a socket wrench to unscrew the spark plug and remove it.

Check the electrode and insulator. If you see buildup, spray brake cleaner onto the plug, and let it soak for several minutes before wiping it with a clean cloth. Reinstall the spark plug, first by hand, and then with a socket wrench for a final tightening. If the problem persists, consider changing the spark plug.

Clear the mower deck of debris.

The mower’s deck prevents grass clippings from showering into the air like confetti, but it also creates a place for them to collect. Grass clippings can clog the mower deck, especially while mowing a wet lawn, preventing the blade from turning.

If the starter rope seems stuck or is difficult to pull, then it’s probably due to a clogged deck. With the mower safely turned off, tip it over onto its side and examine the underbelly. If there are large clumps of cut grass caught between the blade and deck, use a trowel to scrape these clippings free. When the deck is clean again, set the mower back on its feet and start it up.

Clear the vent in the lawn mower fuel cap.

The mower started just fine, you’ve made the first few passes, then all of a sudden the mower quits. You pull the cord a few times, but the engine just sputters and dies. What’s happening? It could have something to do with the fuel cap. Most mowers have a vented fuel cap. This vent is intended to release pressure, allowing fuel to flow from the tank to the carburetor. Without the vent, the gas fumes inside the tank begin to build up, creating a vacuum that eventually becomes so strong that it stops the flow of fuel.

To find out if this is the problem, remove the gas cap to break the vacuum, then reattach it. The mower should start right up. But if the lawn mower won’t stay running and cuts off again after 10 minutes or so, you’ll need to get a new gas cap.

Clean and refill the lawn mower fuel tank.

An obvious—and often overlooked—reason your mower may not be starting is that the tank is empty or contains gas that is either old or contaminated with excess moisture and dirt. If your gas is more than a month old, use an oil siphon pump to drain it from the tank.

(It’s important to be careful as spilled oil can cause smoking, but there are other reasons this might happen. Read more about what to do when your lawn mower is smoking.)

Add fuel stabilizer to the tank.

Fill the tank with fresh fuel and a fuel stabilizer to extend the life of the gas and prevent future buildup. A clogged fuel filter is another possible reason for a lawn mower not to start. When the filter is clogged, the engine can’t access the gas that makes the system go. If your mower has a fuel filter (not all do), check to make sure it’s functioning properly.

First, remove the fuel line at the carburetor. Gas should flow out. If it doesn’t, confirm that the fuel shutoff valve isn’t accidentally closed. Then remove the fuel line that’s ahead of the fuel filter inlet. If gas runs out freely, there’s a problem with the fuel filter. Consult your owner’s manual for instructions on replacing the filter and reassembling the mower.

Inspect the safety release mechanism cable.

Your lawn mower’s reluctance to start may have nothing to do with the engine at all but rather with one of the mower’s safety features: the dead man’s control. This colorfully named safety bar must be held in place by the operator for the engine to start or run. When the bar is released, the engine stops. While this mechanism cuts down on the likelihood of horrific lawn mower accidents, it also can be the reason the mower won’t start.

The safety bar of a dead man’s control is attached to a metal cable that connects to the engine’s ignition coil, which is responsible for sending current to the spark plug. If your lawn mower’s engine won’t start, check to see if that cable is damaged or broken. If it is, you’ll need to replace it before the mower will start.

Fortunately, replacing a broken control cable is an easy job. You may, however, have to wait a few days to get the part. Jot down the serial number of your lawn mower, then head to the manufacturer’s website to order a new cable.

Check to see if the flywheel brake is fully engaged.

The flywheel helps to make the engine work smoothly through inertia. When it isn’t working properly, it will prevent the mower’s engine from working.

If it is fully engaged, it can make a mower’s pull cord hard to pull. Check the brake pad to see if it makes full contact with the flywheel and that there isn’t anything jamming the blade so the control lever can move freely.

If the flywheel brake’s key sheared, the mower may have run over something that got tangled in the blade. It is possible to replace a flywheel key, but it does require taking apart the mower.

Look out for signs that the mower needs professional repairs.

While repairing lawn mowers can be a DIY job, there are times when it can be best to ask a professional to help repair a lawn mower. If you’ve done all of the proper mower maintenance that is recommended by the manufacturer, and gone through all of the possible ways to fix the mower from the steps above, then it may be best to call a pro. Here are a few signs that indicate when a pro’s help is a good idea.

• You see black smoke. The engine will benefit from a technician’s evaluation, as it could be cracked or something else might be worn out.
• Excessive oil or gas usage. If you’ve changed the spark plugs, and done all of the other maintenance tasks, and the mower is consuming more than its usual amount of oil or gas, consult a professional for an evaluation.
• The lawn mower is making a knocking sound. When a lawn mower starts making a knocking sound, something could be bent or out of alignment. It may be tough to figure this out on your own, so a pro could help.
• A vibrating or shaking lawn mower can be a sign of a problem beyond a DIY fix. Usually something is loose or not aligning properly.

Lawn Mower Low Oil Symptoms: Don’t Miss These Vital Signs

Lawn mower low oil symptoms are only a few but quite hard to miss once you know what they are. Whenever your mower stops working midway through a cutting and starts producing noises and black smoke, checking its oil level should be your top priority.

This guide will explore some of the main symptoms that indicate a low oil level in the lawn mower fuel tank. Read on to determine what professional steps you can take in such a case.

• What Are the Symptoms That Your Lawn Mower Has Low Oil?

• – Spluttering Sounds and Noises
• – The Mower Keeps Getting Overheated
• – Mower Starts Smoking
• – Lawn Mower Refuses To Start
• – Damage to Internal Parts

• 1. Find Out Where the Fuel Tank Is Located
• 2. Choose the Best Oil for Your Mower
• 3. Turn the Engine Off
• 4. See What the Dipstick Says
• 5. Get Rid of the Old Oil
• 6. Add New Oil
• 7. Don’t Let the Oil Levels Drop Anymore

What Are the Symptoms That Your Lawn Mower Has Low Oil?

The symptoms that your lawn mower has low oil include making knocking and spluttering sounds while running, quickly becoming overheated, thick black smoke coming out of the mower, an engine that flat-out refuses to start, and damage to internal parts.

These are the major signs you shouldn’t miss while your mower runs.

– Spluttering Sounds and Noises

If the lawn mower starts producing weird noises like spluttering and knocking sounds, it is most definitely running low on oil. Starting and running the engine on low oil levels can ruin the engine’s health, so if you suspect that the engine is low on oil, then immediately turn it off right then and there.

Wait to turn the engine back on until you have checked the oil levels in the fuel tank and refilled it if necessary. There is a very little window of time while running the engine on low oil before it destroys itself irreversibly. We have seen many people persistently carry on despite their mowers producing a knocking sound, only to end up having to replace the entire engine.

– The Mower Keeps Getting Overheated

Overheating is a symptom of low oil levels in the lawn mower that is quite hard to miss. Even if your mower is a push type, you can easily tell that it has begun to overheat. Most riding types of lawnmowers will display on the screen when their temperatures rise above a certain set limit.

If the mower becomes heated a lot during a short period, then this means that it has been running on low fuel levels for a while now. than overheating is needed for the engine’s longevity because of the risk of plastic and metal parts melting from excessive heat.

One major job of oil as fuel is to reduce friction between different engine parts while it runs. When the oil is low, these parts rub against one another, producing heat and damaging each other. You will also find it difficult to run a mower that keeps getting overheated repeatedly.

– Mower Starts Smoking

It’s safe to assume that smoke from the mower is never a good sign. A smoking mower is only sometimes due to low oil levels in the fuel tank, but it is definitely a possibility. If the smoke is coming, especially from the mower’s engine, there is either too little oil in the fuel tank or too much oil.

Having too little oil is a far worse situation because it will destroy the inner working parts of the machinery. To ensure that the smoking mower is low on oil, check if other concurrent symptoms, such as overheating or knocking sounds, are present.

The color of the smoke being produced also gives a good indication as to its cause. When the engine runs low on oil, the smoke from the engine is likely black. If the mower is smoking from too much oil, the smoke will be whitish or grey and will come from the exhaust engine.

– Lawn Mower Refuses To Start

If your mower is of a modern design with automatic responses, it will likely not even start when the oil is low. This is a good thing and will save the machine from unnecessary damage. The spark plug might fire up, but the mower will refuse to turn on. In such a case, your immediate first response should always be to check the dipstick and see how much oil is in the tank.

– Damage to Internal Parts

Your lawn mower will eventually break apart if you are not careful with your engine’s oil levels. Soon you will begin to encounter one problem after another while cutting grass. Some sensitive parts will need to be removed and replaced by newer ones.

Frequently frying engine components of your lawn mower and then having to replace them is a symptom that implies you need to keep its oil level up to date.

What To Do When Your Lawn Mower Is Low on Oil?

When your lawn mower is low on oil, it’s best to empty the old oil from the fuel tank and fill it with high-quality, top-notch oil. You have to find out where the fuel tank is located and make sure that the engine is turned off for this.

Find Out Where the Fuel Tank Is Located

Before adding oil to a lawn mower running low, you must locate the fuel tank first. Depending on the company that manufactured the mower and the type of mower that you have, the location of the fuel tank varies from place to place. The fuel tank is often located near and below the handle in push-type mowers.

If you are still determining exactly where the fuel tank is located, this is where the instructions manual that came with the mower will come in handy. Even if you seem to have displaced the manual, don’t worry. We are sure you can look up online to see the tank’s exact location and how to access it for a refill.

Choose the Best Oil for Your Mower

Undoubtedly, the best oil for all lawnmowers is the SAE-30 one. Not only is this particular oil good for the overall working of the engine, but it will work in all temperature conditions. Some people opt for the slightly more reasonable 5w-30 oil in lawnmowers, but these can be used only in warmer conditions as they tend to freeze over during winters.

Turn the Engine Off

Before doing anything with the mower’s machinery, take strict safety precautions first. You want to avoid putting your hand near the engine with the risk that it might start up accidentally. That is why you must not only turn the engine off and take the key out, but also disengage the spark plug.

The spark plug is usually on one side of most lawnmowers and is identified as a protruded object. Using a screwdriver or a similar tool, you need to unscrew the protective covering over this plug. Spark plugs are very easy to disengage; most will come loose if just rotated counterclockwise a few times.

If the spark plug is too tight and refuses to budge, then fighting with it might damage it. Pour some oil around it to lubricate it and help it loosen up, then try rotating it again.

See What the Dipstick Says

An oil cap will be seen on the fuel tank that you will have to unscrew and take out to observe. Companies make it easy to distinguish by either painting it bright yellow or writing the word oil on it. Sometimes, the cap for the dipstick is marked by a symbol that looks like oil.

Twist the fuel cap in a counterclockwise direction and take it fully out. The oil might drip from the stick, so be ready with a towel or cloth underneath. Usually, a dipstick has two oil markings representing high and low levels. Some more innovative dipsticks will have holes, words, letters, symbols, etc.

As long as the oil lies between the upper and the lower line, that is an acceptable motor oil level, although it would help to keep the oil topped up as much as possible. If your mower has been giving you trouble with the symptoms mentioned above, the oil level will likely be below the lower line.

Get Rid of the Old Oil

When the oil levels within the fuel tank become too low, it’s best to get rid of the old oil before refilling it with a new one. In fact, why not make use of this opportunity to clean the oil tank too? Draining old oil from the fuel tank can be as simple as tilting the mower to pour it all out. However, this method can get too messy, so we suggest you get a siphon pump instead.

Keep a plastic or tin container underneath to collect the old oil from the mower. After tilting the mower on the side of the container, turn the drain plug counterclockwise to pry it open. This plug is screwed a bit tight, so you might need help from a wrench or a screwdriver to twist it loose.

Washing the empty fuel tank with water is going to be of no help at all. Instead, pour a small quantity of clean oil into the tank. Use it to clean the tank’s insides and dissolve the oil-based residues stuck to the inner wall. After that, remove this engine oil because it is no longer clean and fit.

Add New Oil

Now that you have a clean fuel tank, you can fill it with new and fresh oil. Always use a funnel because it helps fill oil neatly without potential spill out. Instead of pouring the oil container all at once, pour in increments. After each increment, check the dipstick to see how much of the tank has been filled.

It would help if you kept filling until the oil level reached the upper level of the dipstick. Make sure not to fill beyond this point even when you feel that space is still available in the tank.

Don’t Let the Oil Levels Drop Anymore

When you regularly add oil to your lawn mower’s engine as per its demands, the chances of engine damage from low oil will go down significantly. As a beginner, you will have to be extra vigilant about maintaining oil levels in the machines. The first time you take your mower out for work, an oil change will be needed after five hours.

Once you start regularly using a lawn mower, there are particular demands on how often the oil needs to be changed. Mowers with larger motors need their oil changed every 50 hours, while mowers with smaller engines need their oil changed after 25 hours.

These are general guidelines, and we recommend you also go through your lawn mower’s manual yourself to see if the manufacturers have given any additional instructions. Keep a can of fresh and premium-quality oil ready, so you can use it whenever the need arises.

Conclusion

Before ending this guide, it’s time to summarize the most important points discussed regarding low oil levels in the lawn mower.

• The foremost symptoms of a mower engine with low oil levels are strange noises like knocking, spluttering, and gurgling of machine parts.
• If black-colored smoke is seen being produced by the engine, then this could also mean that it needs more oil.
• While going through an oil change in the lawn mower, go for the best-quality oil you can purchase, as this investment will increase the machine’s longevity.
• The latest models of lawnmowers will only start if the oil levels in their fuel tanks are adequate, which means the oil levels should be within the upper and lower lines on the tank.

Running a lawn mower on low oil levels is the worst thing you can do to your machine. Keep a vigilant eye on the oil levels while cutting grass, and also be aware of all the symptoms discussed in this article to keep the machine in perfect health.

Top 8 Reasons For An Engine Knocking Sound (4 FAQs)

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When the smooth rumble of your car is replaced by repetitive tapping, scraping, or engine knocking sound, there’s most likely trouble brewing under the hood.

This shouldn’t be ignored as it can lead to a blown engine or other severe problems if not promptly addressed.

Reasons You Hear An Engine Knocking Sound

Engines combine many moving parts, making a cacophony of sound and noise commonly associated with driving a vehicle. If you start hearing an out-of-the-ordinary sound, like knocking, tapping, or scraping, this might indicate a serious problem.

Let’s take a look at a few reasons you might be hearing an engine knocking sound:

Low-Quality Or Low Octane Fuel

All fuel types are designated a number based on their octane rating.

The higher the octane value, the more refined a fuel will be. In other words, the greater the percentage of octane, the more controlled the air fuel detonation will be.

When you put gasoline with low octane fuel rating into your car, it can cause the airfuel mixture to detonate prematurely, causing an engine knocking sound.

Bad Knock Sensor

Most cars nowadays have a knock sensor that detects an engine knocking sound and sends information to the Engine Control Unit (ECU). The ECU then fixes the issue automatically.

If your knock sensor is damaged or broken, the engine knocking can continue unchecked. And a failed knock sensor will trigger the check engine light.

Damaged Or Broken Crankshaft

The piston rings in your cars engine move up and down inside the cylinders connected to the crankshaft. This is regulated by the engine timing system.

The rods and bearings connecting the cylinders to the crankshaft are essential to maintaining the proper clearance between the cylinders and the crankshaft.

When the crankshaft is damaged, and the clearance between the cylinders is not correctly maintained, a striking of metal may occur, causing a rod knock.

Faulty Or Wrong Spark Plug

Spark plugs are responsible for generating the spark in the combustion chamber of your engine. This spark ignites the air fuel mixture, which provides power to the engine.

If your engine has a faulty spark plug or spark plugs that don’t fit the requirements of the specific engine, premature detonation within the combustion chamber may result. This can cause a detonation knock in the car engine.

Lean Airfuel Mixture

Staying on the theme of combustion, the “spark” provided by the spark plugs ignites a compressed air fuel mixture.

When there is a low proportion of fuel in this mixture, the result is multiple detonations and a loud knocking engine noise.

Be sure to check out the engine components that regulate the flow of air and fuel within the engine, like the fuel injectors and the mass airflow sensors — as these influence your air fuel ratio.

Worn Bearings

When your car gets older and experiences engine wear and tear, the bearings on the connecting rod between the cylinders and the crankshaft can start causing a noisy ride with a loud rod knock.

As cars age, particles also build up in the engine, and combustion by-products like carbon deposits, dirt, and grime can form at the back of the rod bearing. These will cause damage to the connecting rod, replacing smooth movement with a piston slap or knocking sound.

Call a mechanic to replace your rod bearing, as these parts are located deep within the engine.

Stretched-Out Serpentine Belt

As a cars engine runs, it turns a serpentine belt connected to various pulleys (powering different accessories) throughout the engine bay. This belt must run at just the right amount of tension to spin silently and smoothly.

An overly stretched belt will be unable to maintain the right level of tension, resulting in a rattling, clicking, or squealing sound that can be mistaken for general engine noise.

Non-Lubricated Cylinder Head

All engine cylinders require lubrication. When a cylinder is running unlubricated, it will generate a knocking sound.

A cylinder will typically lose lubrication when there’s an engine oil leak. Using generic oils with lower flashpoints can also cause poor lubrication in the engine. As such, many car manufacturers recommend using synthetic engine oil to lubricate the cylinder head.

An unlubricated cylinder head can also cause damage to the piston rings and cylinder wall, making this a must-fix to prevent a piston slap.

Tip: If you notice an oil leak, place an oil pan underneath your vehicle to capture any leaking engine oil before performing an oil change.

Still have some queries about the engine knocking sound?Let’s go through the FAQ section.

FAQs About The Engine Knocking Sound

Here are answers to some frequently asked questions about the engine knocking issue:

Can I Still Drive My Car If I Hear An Engine Knocking Sound?

A knocking sound is usually due to a problem with the internal components of an engine. Driving while you hear a knocking noise is not recommended.

The more engine damage you cause to these internal components, the more difficult and expensive the repair job will be. You may even need to replace essential engine parts, which would be costly.

Most of the issues that cause an engine knock will illuminate the check engine light, so keep your eyes on that, and don’t let engine wear become a long-term problem.

What Is A Carbon Deposit?

As fuel burns within the engine, it leaves a carbon residue, aka carbon deposit.

These carbon deposits, or carbon sludge, mainly form within the cylinders. This build-up can clog your cylinders and perhaps an air filter or fuel injector, increasing the amount of compression within the combustion system.

This directly affects your vehicle’s ability to detonate the air and gas within the cylinder, which could be an alternative reason you hear a knocking or ticking noise.

Tip: Add an additive to your fuel injector to eliminate carbon deposits within your engine, or visit a mechanic to clean the deposits out of your engine.

How Much Does It Cost To Fix An Engine Knock?

The cost of an engine knock repair varies depending on where the problem stems from within the engine.

If the knocking sound is simply from a bad knock sensor or poor ignition timing, the repair will cost you between 100 – 400.

However, if there’s more severe engine damage, and you need to replace a cylinder rod, the price could start to travel upwards of 2000.

How Can I Fix An Engine Knock?

Before starting any self-repair job, try performing these quick fixes:

• Use the correct octane fuel (inadequate or incorrect fuel will cause a detonation knock)
• Ensure that you’re using the proper spark plug type for your car engine
• Check and adjust the ignition timing of your vehicle to prevent multiple detonations

If this doesn’t help, start asking yourself questions like “when did the knocking noise start?” or “what type of knocking or ticking noise is coming from the engine?”

You can also try checking for trouble codes by running a diagnostic scanner on your vehicle.

If you’ve diagnosed the issue and know where it’s coming from, and the problem doesn’t involve critical components of your engine, you can try and attempt to fix it yourself.

If you can’t find exactly where the issue stems from, or aren’t comfortable attempting these repairs, let a mechanic do the job for you.

Final Thoughts

If you hear an engine knocking noise, try to address it ASAP to prevent additional damage to your engine components. Contacting a professional auto repair service is your best option to get that knocking engine resolved.

We’re a mobile vehicle and maintenance repair service that makes repairing your car super convenient.

• Auto repair services, such as an oil change or an air filter replacement to more complicated repairs, can be done in your driveway
• Expert technicians will execute vehicle inspections and servicing
• Booking online is easy and convenient, with competitive, upfront pricing
• All maintenance services are conducted with top-quality tools and replacement parts
• RepairSmith offers a 12-month | 12 000-mile warranty

Contact us today for all of your vehicle needs!

RepairSmith RepairSmith makes it easy to keep your vehicle reliable by delivering quality auto repair and maintenance directly to your driveway, with effortless booking, transparent pricing, and trusted technicians.