Working in automotive for the last 20 years as a technician and service advisor has provided me with a lot of information to share.
When your ride is rattling
At some point in time, every vehicle will give an unexpected clunk or squeak noise going over a bump. In worst case scenarios, the car will make these noises over every little imperfection in the road.
The overall purpose of the suspension is to suspend the body of the vehicle, comfortably, over the wheels. If the wheels connected directly the the body of the car by straight bars, it would be the most uncomfortable thing EVER! Think of a seat on a basketball. Everytime the tires bounced across anything it would transfer straight to the passenger. Seatbelts would exist to keep you from bouncing out of your seat. With that in mind, to create a quiet, smooth riding suspension requires springs and rubber bushings that cushion around the pivot points.
Front end suspension
Name that sound!
There are a few variations that are distinctly different:
- The squeaky door hinge. This commonly happens with turns
- The underfoot thunk. Usually present over larger bumps or dips.
- The front end rattle. Rattle noise over every little thing
- The tinny, metallic rattle from under the center of the car. Often heard sitting at a stop. Sometimes it's just an obnoxious buzzing.
Plus a whole gambit of sounds in between! Sometimes, just going for a ride with your service person can really help! However, I'll give the most common reasons for each noise.
A common noise is a grunt/squeak noise that occurs when turning or going over bumps. Many times it's described as the sound of a squeaky door swinging open. This usually comes from the ball joints or tie rods. I will describe these to you in basic terms and their function on most vehicles. The front steering is operated by the power steering rack. Attached to the end of the rack are threaded bars called 'tie rods'. Where the tie rod attaches to the part the wheel is mounted to, (the spindle), there is a ball in socket that allows side to side and limited up and down movement. The spindle is basically where your wheel is mounted. Naturally, as time goes by, the socket and ball of the tie rod begin to wear out. Usually the grease breaks down and the dry friction between these 2 makes a noise similar to a door on squeaky hinges. Some are greaseable, but many are not. Usually by the time you start hearing these noises, you probably should replace the part. If these pivot points fail, you will lose your steering control and suffer greater damage and possibly crash! The good news is that from the time the sound starts to actual part failure is usually quite some time.
The clunk and rattle
Suspension noises are usually created specifically from up and down movement like going over bumps. A very common noise is a clunk or rattle type that comes from the stabilizer bar end links. The stabilizer bar runs horizontally across the front of your vehicle and helps to reduce the lean or sway of the body when you turn or go over uneven terrain. The links on the end connect from the bar usually to the strut or sometimes to the control arm. These end links have rubber bushings that will harden and break down as time goes by. These links will rattle over bumps once the bushings break down. Replacement is the only repair for this.
The same is true of the control arm bushings. They look like big, rubber hockey puck with a hole in the middle. They hug the 2 bolts that hold this arm to the body by the engine area. When the hole gets worn out, it can cause a lot of clunking and very uneven tire wear. This is because the wheel can actually move in and out slightly.
Sounds way cooler than it actually is. The common buzz or rattle from under the middle of the car is usually the easiest to diagnose and repair. The exhaust system has heat shields placed strategically along the length of the vehicle. They perform 2 functions,
- Reflect heat away from the passenger area above
- Bring exhaust temp up to effectively catalyze gas emissions in the converter
If a pebble gets caught between the shield and the exhaust, it can rattle around in there. Or, if a part of the shield comes loose, it can rattle like crazy. Most of the time, a stone can be dislodged or the shield secured very easily.
The search for the sound
There are a lot of places in the steering, suspension and subframe where rubber bushings were installed by the manufacturer to create cushion and damper road force which all help to create a smoother ride. Unfortunately, as all of these break down with age and use, they are all susceptible to making noise. Short of addressing the obvious concerns, pinpointing the exact source of a noise can be difficult. Sometimes it's just a technicians best guess.
Jerry on July 17, 2014: