Diagnosing Noises in Your Car
In addition to shocks and struts, there are control arms, ball joints, bushings, and a few other things that can cause noises in your vehicle’s suspension if they wear out. As for finding these noises, you sometimes need to get a bit creative. Some noises are obvious, such as a broken stabilizer link. It’s easy to spot broken parts. It might not be so easy to spot worn parts. As for those worn parts that might be making noise, look for that orange dust I spoke of when talking about U joints. Orange dust around a suspension part almost always means that part is bad or on its way out.
Ball joints can be tricky, but once you know what noise they make when they’re bad, they can be easy to diagnose. Ball joints are just what they say they are, and are used to connect suspension components.
When a ball joint goes bad, it often sounds like a rusty door hinge. You’ll usually hear this noise when turning the wheel or going over some bumps. This is a dead giveaway. Most suspension noises make noise in one direction; ball joints make noise when moving back and forth and up and down. You can sometimes inject a little grease in a noisy ball joint to get the noise to go away. If it’s not serviceable, you can sometimes remove the joint from what it goes into and exorcize it, meaning you move it around through extreme motion (motion it would never see on the vehicle). This works the lubrication in the joint around and redistributes it. Sometimes the noise goes away when you do this. In fact, there was a TSB on some Acuras demonstrating this very thing. You’d disconnect the joint, move it around a bunch, reinstall it, and the noise would be gone.
Mostly what you find with suspension noises are rattles going over bumps. Those can be just about anything. With a good physical and visual inspection, you can often nail these down. Here’s a video you might find helpful about suspension noises.
You might also find these videos helpful if you’re dealing with a suspension noise.
Probably the most important thing to note here is that not all wheel bearing noise is a wheel bearing. In fact, most times it’s the tires. To make the determination, you can use a couple of different techniques. My preferred method is to run the vehicle on a lift and stop one wheel at a time by using a pry bar to lock the brakes. This helps locate the bad wheel bearing through isolation. This might not work if you have a limited slip differential, and it might make you a bit nervous. Here’s a video showing how I do this without a lift.
Many people believe you can feel a bad wheel bearing by moving the suspected wheel up and down or side to side by hand. That’s not always the case. In fact, a wheel bearing will make noise long before it will click, or show any movement when you try and shake the wheel. The truth is that once a bearing gets loose enough to feel the play, it sometimes gets quiet and doesn’t make noise anymore. It know it sounds strange, but I’ve been burned on this very thing in the past. I had a car once that didn’t make any wheel bearing noise at all, but when you grabbed the tire when it was off the ground, it felt like it was about to fall off.
Another method that’s been brought up in the comments to the above video quite a bit is the slalom method. This involves driving and turning the wheel from one side to the other while listening for the noise. If you make a right turn and hear the noise, the left bearing is bad, and the opposite is true for turning in the other direction. I’ve never tried this, but I’m sure it works, as many have mentioned it in the comments of the above video.
One last method: If you have an infrared thermometer, take the vehicle on a long drive at speed. When you get back and park the car, take the temp reading of both wheels at the hub. The hotter wheel will likely be your bad wheel bearing.
As I mentioned above, tire noises account for more of the wheel bearing-type noises than anything else. A lot of people replace wheel bearings thinking that’s where their noise is coming from. But more often than not, it’s the tires that make that type of noise. To verify a bad tire(s), rotate the suspected tire to the front or back of its current location. If the noise changes or goes away, you found your bad tire. Replace the tire, preferably as a pair, and recheck for your noise.
It’s not a bad idea to visually inspect your tires for signs of abnormal wear. Run your hand along the top of the tire and feel for rough spots or abnormalities in the tread. If you feel any, it’s likely you have an alignment issue, or perhaps some worn or loose suspension parts. It’s worth looking into before you get new tires. Also look for bulges in the tire; be sure to check the sidewall as well as the tread. If you find one of these, replace the tire ASAP.
More information on tire issues can be found in the ‘Vibrations’ article.