A common problem that BMW owners experience as their vehicles age is that their cars can begin to vibrate while accelerating. If you’re looking for the reasons behind a BMW’s vibration when accelerating, this article will help you diagnose the issue and provide possible solutions.
A BMW vibrates when you accelerate due to:
- Damaged CV joints
- Loose lug bolts
- Broken motor mounts
- Bent driveshaft
- Unbalanced tires
- Worn tire tread
- Bad wheel bearings
- Seized brake caliper
The repair for a BMW vibration problem will vary significantly depending on the precise source of the issue. Fixing a loose lug bolt or swapping out a brake caliper is quite simple and can be performed by a DIYer with no experience. Replacing a wheel bearing or driveshaft, on the otherhand, is a more complex undertaking that will require a mechanic if you do not feel confident in taking on a several-hour repair.
Something else to note is that significant vibration in a vehicle is a serious problem and should be repaired as soon as possible.
So, if you’re looking to diagnose a vibrating issue in a BMW, this article will help you find out what needs to be done.
Why Is Your BMW Vibrating When You Accelerate?
Vibration in a BMW is never a good sign. Sometimes vibration can be a symptom of something seriously wrong, and you need to address it before it escalates into something worse and sometimes it can be something extremely minor and unproblematic. Unfortunately, we can’t possibly know for certain until we take a look under the hood.
So, here are some of the issues behind vibration while accelerating with your BMW:
1. CV Joint Is Damaged
A potential problem causing the vibration while your BMW is accelerating is that the CV joints, primarily located at the end of your BMW’s axel points, could be damaged. This is mainly due to wear and tear brought about by the accumulation of water and dirt, which creates unnecessary metal-on-metal friction that can cause the inner CV joint to be damaged, causing failure.
The location of your CV joints will depend on whether your BMW is front, rear, or all-wheel drive. CV joints are part of the CV axles and the CV axles connect your differential to the tires on either end of the vehicle. You can have either two or four cv axles.
The solution: You can potentially resolve this issue by lubricating the CV joint, however, more often than not, you will need to replace the entire CV axle.
CV axle replacement varies in difficulty depending on the faulty one’s location in the vehicle. Front-wheel CV axles are significantly more difficult to replace than rear-wheel axles because of the additional parts you will likely need to remove to replace the axle. Generally speaking, this is a repair for a more experienced DIYer or a professional mechanic.
2. Lug Bolts Are Loose
If your lug bolts are loose, it will create a shaking movement while driving throughout the entire car. This will cause significant vibration in the steering wheel. This is an extremely easy fix but is easily one of the most dangerous problems as a lug bolt or two backing out can cause the other lug bolts to snap, which will then cause the wheel to fall off.
The solution: You need to check the lug bolts and ensure they are tightened to prevent them from backing out. If you recently took your BMW to the mechanic for a wheel alignment or for anything else where they may have needed to remove the wheel I would assume that a loose lug bolt is the likely culprit.
Remember, it is impossible to inspect the lug bolts while the wheel is on the ground unless the bolts are so far backed out that it is obvious. More likely, you will need to get each tire off the ground to inspect the bolts.
3. Motor Mounts Are Broken
Motor mounts, made out of rubber, attach your BMW’s motor to the vehicle’s body. Additionally, they help prevent and reduce vibrations between the engine and inside your vehicle’s body. The rubber absorbs any shaking and, when worn down or damaged, will create a shaking feeling in the car.
BMW engine mount degradation is not something that can be prevented, but luckily, they rarely begin failing before 100,000 miles.
What are some symptoms of a bad engine mount?
- Significant vibration from the engine. You can lift the hood and actually see the engine shaking.
- The engine lifts and falls when stepping on the gas and braking. This is due to the engine mount breaking.
A bad engine mount is a significant problem because many of the components located in the engine bay are fitted tightly. If you continue to drive your BMW with bad engine mounts, you can damage wires and coolant/vacuum lines.
The solution: Enlist the services of a mechanic who can replace the motor mounts and prevent further damage or remove any obstructions between the engine and the vehicle’s body. Alternatively, engine mount replacement is not very difficult and you can save some extra money by doing it yourself. Here is a great video below on replacing an engine mount on an F30 BMW.
4. Driveshaft Is Bent
A bent drive shaft is one of the more annoying problems you can encounter and is significantly more common in rear-wheel drives (but still quite uncommon). The driveshaft transfers power from the engine to the rear axle by bolting into the rear of the transmission.
BMW’s driveshaft is actually a very solid piece, which is why the driveshaft will not typically bend unless the vehicle is in an accident.
What are some symptoms of a bent BMW driveshaft?
- Significant vibration emanating from underneath the vehicle.
- Clunking or knocking noises emanating from underneath the vehicle.
- The car shudders when you attempt to accelerate.
The solution: A bent drive shaft cannot be repaired and will need to be replaced. Take your BMW to a mechanic and get them to field a balanced driveshaft for you to prevent further damage to your vehicle’s undercarriage. Alternatively, you can also have a driveshaft balanced and install it yourself, however, be forewarned that installing a driveshaft will require the removal of most of the exhaust system as the driveshaft sits above the exhaust.
A bent driveshaft can cause damage to the U joints, destroy the differential and transmission bearings and damage the pinion gears. These potential consequences mean that a bent driveshaft should be corrected as soon as possible and you should avoid driving the vehicle until it has been corrected.
5. Tires Are Unbalanced
If you’ve recently replaced your tires, this is the most likely reason behind your BMW vibrating while accelerating. It is possible that the tires weren’t correctly fixed or balanced when the mechanic replaced them. The weight of the vehicle isn’t evenly distributed among all the tires when they are improperly mounted, and the weight imbalance will lead to small vibrations that get progressively worse over time.
You will feel more noticeable vibrations at higher speeds, and you will feel them mainly through your steering wheel.
The solution: Return to the mechanic who mounted your new tires and demand a refund or request that they double-check to make sure they mounted it correctly and to do so at no extra charge.
6. Tire Tread Is Worn Out
Your tire tread is the part of your car that will experience some of the most wear and tear over time, and when the tread is worn out, your tires will not grip the ground the way they should. This will affect the stability of your BMW and cause vibrations.
The solution: If you observe any irregular damage to your tire treads, any potential fixes will be limited to the center of the tread. But if you have irregular damage (a nail for example) near the shoulder or the damage is simply due to normal wear and tear, you will need to replace your tires. Preservation of tire tread requires good driving habits and maintenance of correct tire pressure.
7. Wheel Bearings Are Bad
Bad wheel bearings can cause a variety of problems in your BMW, one of them being vibration felt at the steering wheel. Wheel bearings are an absolutely critical component of your vehicle because they connect your axle to the wheel, which allows your wheels to rotate properly.
What are some symptoms of a bent BMW driveshaft?
- Noise when turning the vehicle. This is by far the most common symptom and what I have experienced on my BMWs when I have had to replace a wheel bearing. Typically you will not notice a notice until you turn the vehicle. When turning, you will hear a clunking noise. THIS IS THE DEAD GIVEAWAY FOR A BAD WHEEL BEARING.
- Uneven tire wear.
- Grinding noise. As the wheel bearing gets worse and worse you will begin to hear noises coming from the wheel regardless of whether you are turning or not.
- Steering wheel vibration.
The solution: I hate replacing BMW wheel bearings, they are significantly more difficult than American vehicles to replace as they are “sealed” wheel bearings. This means that you can’t simply pack the bearing, you have to replace it. In addition, you will likely damage the hub assembly while you are trying to replace the bearing so you will need to swap that out as well.
If you choose to replace the wheel bearing yourself, you will need several specialty tools designed to remove BMW wheel bearings. You can find the kit here.
8. Brake Calliper Is Seized
Finally, a seized brake caliper could cause your wheels to stick. This sticky movement will cause your BMW to shake and will be noticeable when driving at higher speeds, particularly while steering. You will also be able to identify this issue if you smell something burning when you stop and get out of the car.
What are some symptoms of a bent BMW driveshaft?
- The vehicle pulls to one side, especially when you press on the brakes.
- Acceleration is sluggish (this is due to the seized caliper).
- Vibration in the steering wheel.
The solution: Brake calipers rarely fail at the same time. Therefore, there is a really simple and fairly accurate way to identify whether you have a seized brake caliper. Drive the car around for a few miles and then pull the vehicle over. Check the temperature of the car’s rims. If one of the rims is very hot, you have identified the wheel with the seized caliper.
Replacement of a BMW brake caliper is relatively simple and should take a beginner DIYer less than two hours.
Conclusion
We have learned that there could be several causes to why you are experiencing vibration while accelerating your BMW. The problems listed above are by far the most common issues, and each can be rectified by a professional or DIYer. My last bit of advice: do not delay in making the necessary repairs or replacements when you have a significant vibration problem. These issues tend to cause additional problems if they are not quickly rectified.
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