While a definitive check for physical play in a wheel bearing is best done with the car lifted, you can identify initial symptoms such as unusual noises, vibrations, or excessive heat with the vehicle on the ground. These preliminary checks can help you determine if further inspection by a professional is needed.
Initial Checks with the Car On the Ground
Assessing a wheel bearing while the car is on the ground primarily relies on your senses. The weight of the vehicle often masks any physical looseness or play that would be evident when the car is lifted.
Listen for Unusual Noises
One of the most common indicators of a failing wheel bearing is an unusual noise. Drive your car and pay close attention to any sounds originating from the wheels.
- Humming, Grinding, or Roaring: These sounds often increase in volume with vehicle speed. They might resemble the drone of an airplane or a low growl.
- Changes with Turning: The noise might become louder when turning the steering wheel in one direction and quieter when turning in the other. For instance, a bearing on the left side might get louder when turning right (putting more load on it) and quieter when turning left.
- Clicking or Clunking: While less common for wheel bearings themselves, these sounds can indicate a severely damaged bearing or issues with other suspension components.
- Constant Noise: Unlike tire noise, which can vary with road surface, a bad wheel bearing noise is usually consistent on smooth roads.
Feel for Vibrations
A failing wheel bearing can transmit vibrations throughout the vehicle.
- Steering Wheel Vibration: You might feel a shimmy or vibration in the steering wheel, especially at certain speeds.
- Floorboard or Seat Vibration: Vibrations can also be felt through the floor of the car or even the seat.
- Pulsation: In some cases, a bad bearing can cause a pulsating sensation that might be confused with warped brake rotors.
Check for Excessive Heat
After a drive, carefully check the temperature of the wheel hub area.
- Touch Test (with caution): After driving for a bit, pull over safely and carefully touch the center of the wheel (the hub area, near the lug nuts, avoiding the brake rotor). A failing bearing generates significant friction, causing that area to become much hotter than the other wheels. Always exercise extreme caution as the hub and brake components can be extremely hot and cause burns. Use a non-contact infrared thermometer for a safer and more accurate reading if available.
Understanding Physical Play: When to Lift the Car
While the car on the ground can reveal symptoms, the definitive way to confirm a loose wheel bearing is to check for physical play. This test is most accurately performed with the vehicle safely lifted off the ground.
The weight of the car firmly presses down on the suspension and bearings when on the ground, effectively masking any looseness. To accurately detect a loose wheel bearing, the wheel needs to be free to move on its axis.
When the vehicle is safely supported on jack stands and the wheel is off the ground, you can grip the wheel firmly at the 12 and 6 o'clock positions and attempt to rock it in and out of the vehicle. Any noticeable movement, looseness, or a "clunking" sensation indicates a worn or bad wheel bearing.
Common Symptoms of a Failing Wheel Bearing
Recognizing these symptoms early can prevent further damage and ensure your safety.
| Symptom | Description |
|---|---|
| Loud Noise | Constant humming, grinding, roaring, or growling sound, often changes with speed or when turning. |
| Vibration | Shaking or vibrating felt through the steering wheel, floorboard, or seat, especially at certain speeds. |
| Looseness/Play | Excessive movement or "wobble" in the wheel when inspected with the car lifted. |
| Uneven Tire Wear | Scalloped, cupped, or irregular wear patterns on the tire tread. |
| ABS Light On | Faulty wheel speed sensor, often integrated into the wheel bearing assembly, triggering the ABS warning. |
| Vehicle Pulling | The car might pull to one side while driving or braking. |
| Excessive Heat | The wheel hub area becomes unusually hot after driving due to increased friction. |
When to Seek Professional Help
If you notice any of the above symptoms, especially persistent noises or vibrations, it's crucial to have your vehicle inspected by a qualified mechanic promptly. Driving with a severely failing wheel bearing can be dangerous, potentially leading to wheel detachment or loss of control.
A professional will be able to perform thorough checks, including lifting the car to assess physical play, and recommend the appropriate repairs.
