Why Does My Car Sound Like a Motorcycle When I Accelerate?

If your car sounds like a motorcycle when you accelerate, it is likely a problem with the car belt, the drivetrain, the exhaust system, or it is engine-based – specifically the valves, bearings, or pistons in your engine.

Possible Scenarios

Car Belt

Do you also get the motorcycle sound when turning, as well as when accelerating? If so, it could be an issue with the car belt. If you listen closely, you should hear a bit of a squeaky sound as well as the motorcycle sound. It is most noticeable when you are accelerating, but also happens when you are turning if it is a car belt issue.

Basically, what happens is that you get the sound when the pulley doesn’t start properly, causing a lift issue that makes the belt perform inefficiently and noisily.

Drivetrain

The drivetrain is responsible for getting power from the transmission to your wheels, but despite the singular sound of the name, it is composed of several parts. Your drivetrain includes parts like your transmission, axles, driveshaft, CV joints, differential, and more.

If your car is a bit on the older side, then wear and tear on the drivetrain causes your car to accelerate loudly and damage to any one of these parts could cause this.

Exhaust System

Probably the second most likely culprit on the list, your exhaust system is comprised of several parts, such as your muffler, resonator, catalytic converter, and more. As your exhaust system is designed to move those toxic gases safely out of the vehicle, there is a lot of gas and pressure involved. A single leak in any one of the components can cause motorcycle-like sounds during acceleration.

Engine

This is the likeliest cause of the issue (in most cases). It has valves that work with your exhaust system, set to open and close to facilitate removal of gases, and when the valves act up, then the engine becomes quite loud during acceleration.

The bearings and pistons are also potentially a problem here, but damage to any one of these 3 items can cause your car to sound like a motorcycle.

Potential Costs

While we don’t have exact figures since it varies from vehicle to vehicle, we can tell you which of the items below are relatively inexpensive and which ones are going to set you back a bit.  

Car Belt Repair

If the noise that you are hearing is due to a faulty belt, then this is good news. Belts need to get replaced all the time and you can even get one for your vehicle from your local auto repair shop. Even if you just take it to a mechanic, the repair is generally inexpensive.

Drivetrain Repair

If the issue is with the drivetrain, then repair could be quite expensive. The biggest problem is that all of the parts that make up your drivetrain are expensive to replace. The work needs to be done quickly, as well, because the drivetrain is critical to your vehicle’s operation. If your drivetrain breaks down completely, your car isn’t going anywhere.  

Exhaust System Repair

If you’ve got a leak in the exhaust system, the mechanic first has to trace down the leak and then determine what part needs to be replaced. They will put in a new, sealed part and this should fix the issue. This is typically around 2 to 3 hours of work, so you are likely looking at around $300 for repair (this is labor, not the part) but your mechanic can give you a solid estimate.

Engine Repair

If it is an issue with the engine itself, then this is going to be costly. As with the drivetrain, the parts involved when you are hearing motorcycle sounds can be costly to replace. The repair needs to be done quickly before anything gets worse, and any problem involving those pipes, bearings, or pistons is not going to something to ignore.

Summary

To recap, if your car sounds like a motorcycle, then you’ve got an issue with the car belt, the exhaust system, your drivetrain, or the engine. 3 out of 4 of these are costly, so we recommend visiting your local mechanic to get a closer look. Remember, this issue can easily get more expensive with time, so you’ll want to resolve this as soon as possible.

Brian