BMWs are famous around the world for their performance and comfort. BMW offers a number of models; some of the most famous are the 3 Series and 7 Series.
BMW owners love to hear the sound of their engine while they rev it. It’s like music to the ears. However, there is a difference between the sound of a healthy engine and the throbbing or rattling sound coming from the engine.
In this blog, we will have a look at the most common underlying problems that cause a noisy engine.
If your BMW’s engine is malfunctioning and producing unusually loud noises, then you should get it checked at any reputable European auto repair shop.
Knowing The Engine Noises Of When Accelerating
When you press the pedal and your engine sounds a rising note, it becomes really necessary to understand the source of the sound you hear.
The more you accelerate, the more fuel and air your engine will burn, creating high energy levels.
When you demand such power increase, it is the internal components of your engine that create various sounds, and these sounds tend to become more pronounced.
Furthermore, the type of engine, such as inline, V-shaped, boxer, and others, the number of cylinders, and the form of the exhaust system can be the key factors that form the sound of the vehicle.
The sound of engine noise can go from one extreme to another. With some being the high-pitched whining and others being a low rumble.
The motorcycle-like sound is an indication that the engine is overworking and the exhaust can be leaking.
Common types of engine noise you might encounter during acceleration include:
Knock-knock or ping-ping:
Such high-frequency rattling noise is often the result of the fuel in your engine not being burned evenly or at the right time, which can cause damage to the critical components.
Rumble:
That may indicate exhaust issues, like leaks or problems with the resonator, a component of the muffler designed to lessen noise.
Tick-tick or click-click:
When you hear this noise, which is more rhythmic, this might mean lack of oil in the engine, problems with the valvetrain, or even engine rotating parts.
Common causes of the loud engine noise.
There are numerous typical reasons for a noisy engine during acceleration. Hence, each category is also subdivided into several causes.
Exhaust System Issues
The exhaust system is responsible for the gases that are produced in the combustion cycle, and it also muffles the noise produced by the engine. This system always produces loud engine sounds whenever it faces a problem.
It could be from:
Exhaust leaks:
An exhaust leak in the tailpipe or the muffler or an exhaust manifold leak results in a significant increase in the noise level.
Catalytic Converter Failure:
The catalytic converter is one of the devices which serve to treat the exhaust gases, and if it happens to fail, the car’s engine becomes louder.
Exhaust Manifold Leak
The exhaust manifold of your car takes these noxious gases from the cylinders and delivers them to the catalytic converter.
The sound from the leaking exhaust manifold that is mostly heard when you accelerate is very loud. This is the sound of the gases being released. Another thing that is also common is a ticking or a taping sound at the startup.
Engine Misfires
These are instances when the air-fuel mixture fails to burn as it should, creating imbalances and vibrations.
Fuel injection system issues:
A fuel injector that’s clogged or not working properly can deliver either too little or too much fuel to the cylinder; this results in misfires.
Ignition problems:
The spark could be weak, spark plugs could malfunction, or the ignition coil could be faulty, and this could lead to the fuel not being ignited properly.
Worn or Faulty Components
Over time, the wear and tear on engine components can lead to increased noise:
Piston slap:
This happens when the piston moves up and down in the cylinder and hits the cylinder wall creating a characteristic tapping noise.
Worn bearings:
Bearings are the supporting elements for rotating shafts in your engine, and they can produce a knocking sound when they become old or worn out.
What Symptoms You Must Recognize When Troubleshooting Loud Engine Sounds
Lower Fuel Economy
The main symptoms of an exhaust problem are loud noises and poor fuel economy, so if you notice these signs, you need to have your exhaust checked.
Exhaust leaks lead to your engine working harder and poor engine operation results in burning more fuel. Such a situation directly translates to your car using more fuel to perform its job.
Vibration In the Cabin
An exhaust leak, along with a hissing sound can cause unusual vibrations of the steering wheel, foot pedals or driver seat.
In case your car has a power loss problem, for example, poor acceleration, then most probably the reason for that problem is the leakage.
Another reason for the cabin vibration can be a hole in your exhaust or that the exhaust system is disconnected.
Cabin vibrations may indicate a problem elsewhere with your engine, and that the engine may be running in sub-optimal conditions.
Note Backfiring, Sputtering Noises
If you hear a loud backfiring and sputtering noise from the back, it points the engine tuning problems rather than the issues with exhaust system.
Probably there is something wrong with the engine instead of the pipes, catalytic converter or muffler.
How To Fix Loud Engine Noise in BMW?
Check and Replace the Engine Oil:
One of the simplest and undeniably efficient ways of damping the noise is through proper lubrication which is one of the main components of engine system.
Oil is intended to mitigate the effect of friction on moving engine parts by lubrication and as a result, minimizing noise production.
With time the oil will get oxidized, or eventually the additives from premium oil will get depleted, which can cause a noisy engine due to the high internal friction. The right oil level and quality check are imperative to maintain healthy engine condition.
Inspect and Replace the Serpentine Belt:
The serpentine belt which is also known as a drive belt is the one that provides its engine with necessary components including alternator, power steering pump and an air conditioner compressor.
A belt that is worn-out or has a loose fit will frequently generate a squealing or rattling sound, notably during acceleration.
Assessing a belts condition thoroughly by looking for signs of wear like cracks, fraying or glazing is very vital.
Address Exhaust System Leaks:
The exhaust loses can make loud roaring or rumbling sounds from under the engine because of that either.
Leakage is usually caused by the radiator hose, a ruptured valve, or at the exhaust manifold gasket, muffler connections, or exhaust pipes.
As exhaust gas leaks, they not only cause noise but may compromise also the power and fuel efficiency of the engine at the same time.
Diagnosing exhaust system for obvious leaks is suggested with a check for signs of smoke or soot.
Investigate and Rectify Engine Mount Issues:
Engine mounts are of paramount importance to the whole of this concern doing the engine locally and to make it stay firm and slightly vibration free.
With time, these mounts may get worn out or broken and these issues may cause an increase in engine noise and vibration getting through to the cabin.
The integrity of the engine mounts should be inspected for damages, such as cracks or leaking fluids, if any of these are found, the underlying problem should be addressed as early as possible.
Takeaway:
Careful observation of the type of sound coming from the engine is important to determine what is the reason behind the noise.
For an in-depth review of unwanted engine noises in your BMW, you should contact Erics Car Repair. We have a team of expert mechanics who know the complexities of European cars and provide the best possible service. So, call us at and book your appointment. 713-352-8058.
