Knocking sound
The car would start up and then quit. Finally, I got the car started and there was a knocking sound.
Experienced mechanics share their insights in answering this question :
Hello. It sounds like there is something broken in the engine internally. A push rod could be bent, a lifter could be stuck, or the engine bearing could be messed up. Have your vehicle’s noise inspected by a certified technician, like one from your mechanic, to determine whether your engine would need to be replaced or rebuilt in order to fix this problem.
How to Identify and Fix Common car Problems ?
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Knocking occurs when fuel burns unevenly in your engine`s cylinders. When cylinders have the correct balance of air and fuel, fuel will burn in small, regulated pockets instead of all at once. (Think sparklers, not fireworks.)
Description: A light, metallic knocking sound, usually under acceleration. Cause: Knocking is most commonly attributed to improper ignition timing, lean air/fuel ratio, overheating, or improper fuel octane level.
Engine knocking often occurs when the air-fuel mixture is incorrect. To counter this, you can add an octane booster in the mix. This can help ensure proper octane rating, which can then stop the knocking. The recommended minimum octane level in the US is 87.
An engine knock can usually be attributed to a detonation problem, which is why the knocks shouldn`t be ignored. Bad engine detonation can cause catastrophic engine failure if the problem is left unchecked. Techway Automotive can inspect your engine and find the cause of your engine knock.
If you do experience a knocking sound coming from your engine, it`s important to stop driving immediately and have a qualified mechanic diagnose and repair the problem. Allowing rod knock to continue unchecked can lead to serious damage to your engine and should be taken seriously.
The most common reasons a Hummer H2 engine makes a ticking noise are low oil level or pressure, an issue with the ignition system, or an exhaust leak. Search our network of RepairPal Certified shops near you to speak with a technician about your issue.
In case of a knock sensor failure, the PCM may not be able to recognize or fix the spark knock frequency. The failed sensor can result in a metallic pinging noise from the engine. You`ll also notice that the noise gets most prominent when the engine is under a heavy load.
Engine knocking may be caused by worn-out engine bearings. If the bearings are worn, they will not be able to support the weight of the engine, which can cause it to knock. Replacing the bearings may fix the issue.
Engine knock isn`t always the easiest car problem to repair. Here are a few of the most common solutions to knocking issues. Timing belt replacement: Most smaller cars, including most four-cylinder sedans, will use a rubber belt to regulate and control your engine`s timing.
Low Engine Oil
A low oil level can cause engine knocking. If you get lucky, the noise may subside when you refill the engine with oil. In most cases, however, once the oil level gets low enough to create knocking, damage to internal engine components has already taken place.
If the smooth rumble you`re used to coming from your engine is replaced with a repetitive tapping or pinging sound that becomes louder and faster as you accelerate, that`s a classic sign of engine knock.
Engine knocking occurs when the fuel in your engine`s cylinders burns unevenly, and this causes knocking or a pinging sound. It usually happens when the engine`s running, but sometimes you can hear the sound while it is idle or revving up.
A knocking sound coming from your car`s engine can indicate an issue with the crankshaft journal and bearing, which are hitting each other. It`s not exactly a simple fix, so auto shops tend to charge anywhere from $2,000 to $3,000. Some repairs can run up to $4,000 if the damage is severe.
A gasoline engine is not prone to knock at high rpm any more than it would be prone to knock at low rpm. A gasoline engine that knocks or pings at any time is caused by gasoline that is too low in octane or timing too far advanced.
When a CV joint becomes damaged, the axle loses its flexibility, and will make a constant clicking noise when the wheels are turned.
Yes, a bad or slightly out of calibration O2 sensor can cause knock/pre-ignition.
Knocking can cause overheating of the spark-plug points, erosion of the combustion chamber surface, and rough, inefficient operation.
Diesel fuels are actually very prone to knock in gasoline engines but in the diesel engine there is no time for knock to occur because the fuel is only oxidized during the expansion cycle. In the gasoline engine the fuel is slowly oxidizing all the time while it is being compressed before the spark.
The excess oil can create air pockets in the oil, causing it to foam and reducing its effectiveness in lubricating engine components. This results in unusual engine noises, including knocking, tapping, or ticking sounds.
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.
As we`ve discussed in the past, piston slap is usually more of an annoyance rather than an issue compromising engine performance or durability.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Knocking sound at the front end
ANSWER : The first thing is to duplicate the problem with a mechanic because they cannot fix what they cannot hear. Most mechanics want to verify a problem, so they can see if the problem is fixable. The noise is most likely coming from the lower control arms of the suspension or the struts. Only a thorough inspection and verification can find and solve these problem. I recommend having a mechanic drive it with you to duplicate the problem and then have an experienced mechanic inspect and diagnose the steering and suspension noises.
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Car sounds like golf cart when revving and braking; also leaking fluid; sound fades as car warms up
ANSWER : Hello,
There are a number of things that could make an engine noisy when starting up. Depending on the specific type of sound you are referring to, this will determine how to properly diagnose. If there is a bit of a hissing sound, this may be a sign of a vacuum leak. If this is more of a shrieking sound, this may be a sign of a worn out or out of adjustment serpentine belt. If there is a bit of a howling or growling sound, this may be a sign of a worn out or low on fluid power steering pump. A rattling or pinging sound may be caused by an ignition problem. An engine can ping (or knock) due to an improper combustion process. A "spark knock" is the result of combustion occurring too early. Early combustion can occur from carbon buildup inside the combustion chamber, a lean air/fuel mixture, and advanced ignition timing (spark plug firing too soon). A clattering type sound may be a result of improper lubrication in the valve train which could be a more serious problem and should be addressed as soon as possible. I would suggest having an expert from YourMechanic come to your location to diagnose and inspect your vehicle to ensure everything is in proper working order.
There are a number of things that could make an engine noisy when starting up. Depending on the specific type of sound you are referring to, this will determine how to properly diagnose. If there is a bit of a hissing sound, this may be a sign of a vacuum leak. If this is more of a shrieking sound, this may be a sign of a worn out or out of adjustment serpentine belt. If there is a bit of a howling or growling sound, this may be a sign of a worn out or low on fluid power steering pump. A rattling or pinging sound may be caused by an ignition problem. An engine can ping (or knock) due to an improper combustion process. A "spark knock" is the result of combustion occurring too early. Early combustion can occur from carbon buildup inside the combustion chamber, a lean air/fuel mixture, and advanced ignition timing (spark plug firing too soon). A clattering type sound may be a result of improper lubrication in the valve train which could be a more serious problem and should be addressed as soon as possible. I would suggest having an expert from YourMechanic come to your location to diagnose and inspect your vehicle to ensure everything is in proper working order.
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Loud knocking sound when engine is running
ANSWER : Internal engine components each have their own signature noise. An experienced technician can often get a good idea of what is causing a knock by listening to the sound. A connecting rod bearing usually sounds off when you rev the engine up to about 3000 RPM then back off of the throttle. A main bearing has a low pitched knock that is stronger when under a heavy load. Bad pistons will also respond to load, but have a higher pitched sound. There could be any number of other causes of your engine noise and the best thing to do is have an experienced ear on the case. Contact Your Mechanic to have a technician come to your home or office to listen to your engine knock and advise you on what to do about it.
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My engine has a ticking knocking type of sound. It runs fine not buring oil or losing coolent. Sounds like the valves taping
ANSWER : On a 1998 engine with 147,000 miles, the noise could come from anywhere. I typically check the engine oil level when cool to verify it is correct. Then, I run the engine for 5 minutes, shut it off, and check the engine oil level again.
If after running it for a short time and the engine oil level is lower, then it is likely you have a sludge build-up in your oil return passages preventing oil from draining back to the oil pan. If so, maybe an engine oil flush is in order. At the mileage, sometimes an oil flush may do harm to your piston rings or may help. You never really know.
If the oil level is correct after running the engine, you should have an oil pressure gauge connected to the engine to verify that it is within specifications to factory numbers to verify the oil pump is working properly.
An engine tapping noise could be anything from connecting rods on the crankshaft to an engine valve lifter. If the noise is a knock-knock in a repetitive motion at a slow speed, I would suspect lower engine problem, like a connecting rod (which requires a complete engine rebuild). If the noise is at a higher frequency, then I would think you have a valve issue which could be repaired at a much lower cost.
Based upon mileage, the feeling of how the engine runs, engine codes (if any), and an unknown level of maintenance, it is difficult to determine the exact issue. You may need an engine repair, a new engine, more oil, an oil pump, or just live with it. I’d have a certified mechanic take a look at it to diagnose and fix the sound that’s coming from your engine.
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Just put on new brakes and replaced driver side tire. Now there’s a knocking sound when I accelerate or turn right (which intensif
ANSWER : Hi there. If you replaced only one tire, this could be an interior wheel weight hitting against the brake caliper. It could also be an issue with a steering stabilizer bar bushing, CV joint or other suspension component. It might be a great idea to have one of our professional mobile mechanics come to your location to complete a car is making a noise inspection, so they can isolate the root source of this noise and recommend repairs that will resolve the issue.
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The front tire is making a knocking sound when I accelerate
ANSWER : The noise could be a from a tire that is separated or one of the front axles joints being bad. If you do not feel anything in the steering when the noise is happening, then the noise is most likely from an inner axle joint on one of the axles. I recommend having the front end checked by a mechanic, like one from YourMechanic. They will be able to diagnose the knocking noise and make sure that any repairs that are needed are done properly.
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Knocking sound when going over bumps in road
ANSWER : Without being able to hear the noise it will be hard to make an accurate assessment, but worn or damaged strut mounts can be extremely noisy while driving over bumps and exhibit a noise similar to what you describe. However, this is only one possibility and the entire suspension system should be inspected. Chassis ears may need to be used while the vehicle is traveling over bumps to determine the source of the noise. You may want to enlist the help of a mechanic, such as one from YourMechanic, who has the expertise and equipment to determine the source of the noise and correct the issue.
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After I replaced my center bearing, a knocking sound from under the truck had occurred, and it has been slowly getting worse.
ANSWER : Hi, thanks for writing in. It sounds like you have a drive shaft or a half shaft issue. When you get under your car, try moving the axle back and forth. Any play could potentially be your sound. If you do get movement, remove your tire and tighten the nut on the hub and maybe this will solve your mystery. If not, check your drive shafts and see if you have play in them also. I am sure one of theses are your issues. I hope this helps. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this noise issue for you, and make or suggest any repairs as needed.
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