At American and Foreign Garage, our technicians can identify any abnormal noises your car may be making. Unusual noises most often indicate a component or system which is not functioning properly; something is broken or worn out. Sometimes these noises are caused by a minor issue; sometimes they are a symptom of a problem which is severe; or about to become severe.
Squealing when applying brakes: This could have a number of causes from something as simple as dirt or brake dust on the brake rotors, pads or shoes to something more ominous, such as badly worn pads or shoes. It could also be from a wear-indicator on a pad signaling that it is time for new brake pads. Noisy brakes can indicate a serious safety issue, and so it is important to determine the cause to ensure safe and reliable operation.
Scraping or grinding when applying brakes: If the squealing has turned into scraping, this usually indicates bare metal rubbing against bare metal. If this is the case, the brake friction material has been completely worn away on at least one brake pad, and every application of the brake pedal is doing further damage to the rotors. Metal-to-metal brakes will almost always require replacement of the brake rotors, so it is best to monitor brake wear regularly and replace the pads when the friction material approaches the end of it’s service life.
Clunking when braking: Often, these noises indicate that a brake caliper or other hardware is damaged, missing or improperly mounted. Braking imparts unique forces into the car, which can cause shifting if component mounting points are loose or broken.
Any sound when turning a corner: These are often related to the steering linkage. It may require lubrication, or a component could be damaged and require replacement. Corners also impart side forces onto the vehicle systems, which can cause shifting if the mounting points are loose or broken. Wheel bearing failure is another problem which often shows up – first – as a noise when cornering.
Hissing or sizzling under the hood: This is usually noticed when the engine is first shut off, and indicates that something is leaking. Coolant or oil could be leaking onto a heated engine part, such as the exhaust manifold; a vacuum line could be leaking; or the engine cooling system could be losing pressure or over-heating.
Knocking in engine compartment: A “knock” is most often used to describe the sound of detonation. Detonation is when the fuel spontaneously explodes, rather than properly burning along the flame front initiated by the spark plug. Fuel which is contaminated, poor quality, or of insufficient octane is the most common cause. Carbon build-up, ignition problems, and improper air/fuel ratios are other possible causes. Detonation can lead to severe internal engine damage if not corrected. The other engine sound, often described as a “knock”, is heard when internal engine components are colliding, due to wear, deformation, or looseness. In many cases, if this internal knock is audible, the engine may need to be rebuilt or replaced.
Low-pitch humming or whirring under car: This could have any number of causes. If it changes with vehicle speed, the differential may need lubricant, the transmission may be failing, the universal joints may be worn or a wheel bearing could be damaged. Unfortunately, the sounds under a vehicle tend to reverberate and echo making it very difficult to pinpoint the source. Our technicians have the tools needed to identify these noise sources, and can perform any repairs needed to correct the problem.
Rattles from beneath the vehicle: Most often, under car rattles indicate loose exhaust system components.
Squealing or chirping on acceleration: This usually indicates a slipping belt. The belt itself could be worn, or an associated component, such as a belt tensioner, belt idler, or accessory pulley has failed.