Q: Knocking noise underneath car.

asked by on

When driving my car, I hear a knocking noise coming from underneath, usually worse at slower speeds (45mph or lower). When I accelerate, the noise dissipates but will return when I'm coasting or on the brake. It makes this noise when I'm going straight and when I'm making left hand turns, but not as much when I'm turning right. It sounded like it could be a tire problem with the windows down (although I was told its something to do with the axel), and it comes from the front drivers side of the car. It also makes the steering wheel shake a little bit.

My car has 100000 miles.
My car has an automatic transmission.

A: Hi, thanks for writing in. Diagnosing the e...

Hi, thanks for writing in. Diagnosing the exact source of a vibration or noise is typically only possible through an onsite inspection. However, after reading the symptoms you're describing, the two possible suspects may include the wheel bearings or the CV joints. Both components can cause steering wheel vibration at speeds and can also cause knocking sounds as the wheels turn. Here at YourMechanic, we can have a technician come to your home or office to inspect and diagnose this noise issue for you, and make or suggest the necessary repairs.

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Car makes a thumping sound on passenger side when going over 25 mph

A thumping noise is most likely coming from the tire. Have the tires inspected to see if something is in one of the tires or one of the tires has a broken steel belt. You should not drive the vehicle...

Q: Weird noise when engine is running.

If the belt was replaced already it sounds like it may be coming from the power steering pump. Have a qualified technician inspect your engine noise. If the pump is making noise it needs to be replaced.

Q: Is this a good car and what are some problems with it?

Hello. This is a very good car for insurance purposes. The car is quite fast and can have up to 238 horsepower and looks very sporty. The reason this car is good for insurance is all that horsepower only comes...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...