Here’s Why Your Car Vibrates When Accelerating
Vibrations in your car indicate a bug, not a feature
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Of all the annoying issues that a vehicle can develop, vibrations are among the most irritating. Not only is the vibration itself upsetting, but trying to get to the bottom of the issue is a major pain. There is a litany of reasons why a car can start vibrating under acceleration, and many of the causes are expensive to fix.
This might make you wonder why you wouldn’t just deal with the vibration and move on with life, but that’s a bad idea. As you might imagine, your car wasn’t designed to vibrate when it moves, and a newly-developing vibration isn’t something to ignore. It can cause damage to other parts of your car and may even pose a safety issue as you're driving down the road.
The good news is that an experienced mechanic can help identify the issue in no time, and you might even be able to do some of the repair work yourself. The Drive’s crack team of researchers have spent enough time dealing with the issues to know a thing or two about them, so let’s dive in and figure out what’s wrong.
Why Is My Car Vibrating When Accelerating?
That’s not a simple question to answer as there are a variety of potential reasons. That said, those reasons all come down to being related to your car’s acceleration and/or connection to the road. Before we get too deep into the weeds, let’s talk about the parts most likely related to your bad-bad-bad vibrations.
Understanding the Parts that Contribute to Vibrations
It’s understandable that you may not have the depth of knowledge that we do, not everyone can commit to memory the engine codes of every BMW ever made or know the pigment differences between Porsche’s wide array of colors—our spouses would love for us to just remember to load the dishwasher. To bridge that gap, we’ve compiled a little list of parts related to what could be causing vibrations when you accelerate.
To be overly simplistic, axles are the part of your car that hold the wheels. Unless you drive a 6x6 or a large commercial truck, there’s a good chance that your car only has two of them.
Calipers are the part of your car’s braking system that physically squeezes the rotors to make the car stop. The brake pads are mounted into the calipers and provide the friction needed to slow the car.
Your vehicle’s engine and transmission send power to a differential and on to the wheels through a driveshaft. It rotates to transmit that power and torque, so a bend can cause major vibrations as you accelerate.
Just as the name would suggest, motor mounts are the part of your vehicle that physically attaches the engine to the frame. When you rev the car, the engine moves quite a bit, so it’s important that the mounts are functioning properly to keep vibrations and excess movement at bay.
Possible Causes for Vibrations When Accelerating
Now let’s take a look at what could be causing the vibration.
The CV joints, or constant velocity joints, are a part of your car’s axles and are typically intended to last a long time. However, if the plastic boots that protect them get damaged, dirt can leak in and lubrication can leak out, causing all sorts of problems.
You could have a damaged or broken motor mount. Motor mounts are the things that attach the engine to your vehicle’s frame. That sounds serious because it is, and damage to one or more of the motor mounts can allow the engine to vibrate and move around when you press the gas pedal.
Tire Out Of Balance
Having a tire out of balance is annoying, but if that’s the cause of your vibration, you can count yourself lucky. Balancing a tire, or even replacing it, is far cheaper than replacing a motor mount or CV joint.
Loose Lug Nut
One of your wheels could be loose. Occasionally, the lug nuts that attach the wheels to your car can come loose, which can cause that wheel to wobble on the hub while the car is in motion. This is obviously not something that you want to have happened, so it’s best to stop and use your vehicle’s spare tire kit to tighten the lug nuts if you notice an issue.
Bent Axle Or Driveshaft
A bent driveshaft will be noticeable in a rear-wheel-drive vehicle, where the engine and transmission must send power to the rear wheels through the driveshaft. As it turns, a bend can cause it to vibrate. The same is true for bent axles, though you’ll notice them no matter which wheels are being driven.
This is especially true for a seized or stuck brake caliper. If that happens, one or more of your wheels will have brakes that are being constantly applied, which can cause vibration at speed.
Are These Issues Serious or Dangerous to Drive With?
Look, we’re not up here spouting off automotive wisdom for our health. Well, actually, we are. If you decide to keep driving and ignore the issues we listed above, you’ve got a not-zero chance of causing an accident that hurts you or someone else on the road. Even a tire that is out of balance can cause safety issues with your car and can make it harder to control at highway speeds.
How Much Does it Cost to Fix the Vibration?
If you’re lucky, the vibration you feel will turn out to be something simple, like a tire that needs balancing. In these cases, you might get off for little to no money, especially if your tire shop offers extended services on products purchased at their location. Keep in mind that these are estimated costs derived from average costs. Your experience could differ wildly, so use this only as a starting point.
As for the other issues, count on service costs that look like this:
Replacing a CV joint is expensive, no matter the vehicle. The parts alone can cost upwards of $400 to $500 in some cases, and the labor will drive that price even higher. Count on spending somewhere between $500 and $1,000 to replace your CV joint, more if there are multiples that need to be pulled.
If you’re unlucky, you’ll be spending somewhere between $500 and $1,000 on average to replace the driveshaft.
This one isn’t all that bad, actually. Replacing motor mounts can cost as little as $200, but can range anywhere from there to $600 or more.
Prices for these two are hard to nail down because of the number of parts that could be responsible for malfunctioning brakes. You might find that the fix is as costly as a caliper replacement, which can cost up to $800 in come cases, or as simple as having the brake pads replaced.
Tire balancing can be free, in some circumstances. Tire shops sometimes offer free balancing and rotations for products purchased there. Even if you end up having to pay, the job should cost less than $20.
Can You Repair These Issues Yourself?
Sure you can, but keep in mind that some of these things are quite complex and time-consuming. You’ll also need a space to work that is ideally not on the street. If you’re thinking about diving in on some of these issues yourself, be sure to grab a maintenance manual for your car so you know the details of your specific make and model.
Sometimes You Need a Certified Mechanic
As much as The Drive loves to put the "you" in do-it-yourself, we know that not everyone has the proper tools, a safe workspace, the spare time, or the confidence to tackle major automotive repairs. Sometimes, you just need quality repair work performed by professionals you can trust like our partners, the certified mechanics at Goodyear Tire & Service.
You’ve got questions, The Drive has answers!
Q: So What Causes Broken Motor Mounts?
A: If you’re abusive and drive your car at full throttle everywhere you go, you’ll be putting excess wear and tear on the motor mounts. Conversely, sometimes it’s just age-related wear and tear that cause motor mounts to go bad.
Q: Ok, Then What Causes Bad CV Joints?
A: Believe it or not, the only thing standing in between your CV joints and the outside world is a plastic boot. If that boot or its anchors break or tear, dirt and other road grime can get in and gunk up the works.
Q: That Makes Sense, But Why Is It So Bad To Drive A Vibrating Car?
A: We take it you’re one of those people who can calmly drive well past the point of the fuel light coming on, and that you’re happy ignoring things like whining serpentine belts.
A: Exactly. Even if you can stand the annoyance of a car that vibrates under acceleration, you’re running a major risk of being in or causing an accident that could hurt you, others, or your vehicle.
Q: All Right, All Right, I’ll Fix It.
A: We’d high-five you, but, you know, we’re on the internet.
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