Engine Sounds Loud When Accelerating: 7 Reasons & Fixes!

It can be annoying and even embarrassing when your car engine makes rattling, squealing and other ridiculous sounds while accelerating. These noises are fairly common in old vehicles with old engines but there is much more concern when the sound is coming from a new or moderately old one.

Although numerous reasons can cause this, there some very common problems that have been outlined over the years. This article will not only outline the reason for these vehicle defects but also outline the common fixes for these issues.

7 Common Reasons and Fixes

1. Squeaking from loose or worn out belt

This is one of the most obvious reasons a vehicle makes loud sounds during acceleration. In this case, the situation is confirmed if the sound is similar to squeaking or squealing noise rather than loud busts.

This sound is caused by either a loose or worn belt. It can also be caused by the failure of the pulley system which the belt works on to start when accelerated. When the belt system rotates in the engine as it ignites during acceleration, but instead of a smooth rotation, the rough or loose parts of the belt make loud squealing noises against the pulley system.


When the belt noise is concerned, there are two basic solutions you can always opt for; one is to change the belt to a new one, the other is to change the pulley system. The decision between these two depends on the type of damage or the degree of its effect on the engine. Sometimes, it is only the belt that is worn out, and the solution here is to change it to a new one.

The belt could have also been loose, and tightening it will do the trick. But there will be a need to consider changing the pulley system as a whole if the belt is in good condition and only having issues with its free movement along with the pulley.

2. Loud exhaust system due to a hole

This is in every way related to the fault that is hidden deep down in the muffler, converter, and resonator of your vehicle’s engine. These parts are supposed to help move all the exhaust fumes and noises your engine makes away from your notice. A leak therefore in any of them would allow the noises not meant for you to come your way, because the engine has to do more work, and the mufflers get to do less.


If your engine is releasing more sound than it’s supposed to due to leakage, the solution is to locate and identify the point of this leakage. Simply by following the rumbling sound, the exact location of the loud escapees can be identified, and it is only a matter of changing the gasket afterward. Since each joint of the exhaust have gaskets, you only need to replace the gasket for the joint affected by the leakage.

It can be more tasking if the leakage is due to a big hole because you have to change the whole exhaust in that joint or better still take your vehicle to a muffler repair shop for a quick weld of a new pipe to replace the aperture and ensure your exhaust system is leak-tight.

3. Ticking or screeching noise due to bearing failure

Ticking or screeching noise coming from an engine is a common complaint. Technically it is caused by the failure of bearings to spin the cam and crankshafts to the required acceleration levels. This noise is inherent when the vehicle accelerates because the bearings begin to move faster.


The only viable solution when your engine makes noise due to bearings failure is to change the bearing parts. This is a stressful process even for professionals as there is a need to go very deep into the engine to work with the bearings.

The faulty or dislodged bearings should be replaced with newer parts and the rusty parts well lubricated. Doing this in the right way will restore your vehicle to the solemn state it used to be, although this service is recommended to be left in the care of a professional.

4. Piston Wearing/Engine Knocks

The moving piston is one of the heavy-duty workers in the engine. It moves vertically up and down to ensure a continued spinning of the engine, which is much needed during acceleration. This movement is silent when the piston is in good condition, but once there is wear in its part, it produces a loud sound in the engine too. The sound heightens during acceleration and is why you might notice it better when you turn up the speed.


Piston wears arises due to extended usage or misplacement of the piston rings into their positions. Hence, the best approach to solving this problem is by correctly placing the piston rings during installation and ensuring that they are not displaced when your start your vehicle. The right amount of rings should also be used when installing your piston with a DIY approach. Lubricating the piston is another viable solution that can be used when your engine makes a disturbing sound during acceleration.

5. Knock sensor malfunction

With modern vehicles, there is often a balance between the fuel injectors, air/fuel ratio, and even the timing as it is computer-controlled. The control allows the engine to always remains noise-free even when there is no balance between these factors.

But the story changes with your engine when the knock sensor is no longer functioning effectively. The sensor fails to maintain balance in the engine, therefore the engine can knock as many times as possible until it draws your attention during acceleration.


The general approach is to fix or change the knock sensor. However, since this solution is limited only to vehicles with automated controls, manually controlled vehicles will have to be inspected for changes in their air/fuel ratio and other conditions that result in engine knocks.

Here, the appropriate solutions can then be applied to each of the conditions noticed in the engine. For easy diagnosis of these engine knocks conditions and appropriate solutions to apply, reference can be made to this piece on engine knock types.

6. Rattling sound caused by broken heat shield

Heat shield is a necessary component for every exhaust. But these shields are susceptible to frequent damage because of their positions below the vehicle and heated state during vehicle motion. Damage to the heat shields will be identified by the rattling loud noise emanating from your vehicle’s engine during acceleration mainly due to the increased work rate of the engine.


Fixing a broken heat shield is similar to the installation of an exhaust pipe joint. There is however need for some expertise in this aspect, because of the consequences attributed to wrong fixes. The heat shield can be fixed at a local shop near you at an affordable price, but getting a replacement done can be quite expensive but necessary when the shield has suffered great damage.

7. Rattling due to a transmission problem

There are many activities carried out in transmission, and neglecting this important part of the vehicle when lubricating can cause a defect in its actions. This defect is commonly discovered through the rattling sound made by the engine.


According to recommendations, transmission fluids ought to be changed every 30,000 to 60,000 miles of your vehicle’s movements. However, not everyone likes to keep track of their travel periods, hence, the fluid level needs to be checked regularly to ensure that it does not go below the acceptable point. If it has gone below this point, you simply need to refill it to the appropriate quantity and save your vehicle from making unnecessary noise.


As there are different types of sounds made by the engine during acceleration, so there are different reasons behind each sound. Understanding the true reason behind each sound will not only help you figure out a contingency plan easily but also save you the stress and energy of running diagnostics on the vehicle just because of the sound it makes during acceleration.

Also, with the right solutions applied, the problems can be dealt with as soon as they are discovered in your vehicle. The solutions and fixes to the problems have been outlined in this piece to make the process faster and easier for you. Hope this helps!

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