Diagnosing Automotive Problems By Listening To Your Car's Noises

When your vehicle runs properly, it does so without calling attention to itself. Thus, when strange noises occur, they stand out. You might hear pinging, hissing, and screeching sounds coming from under your hood; you may hear squealing or scraping coming from your brakes; or you might hear a slapping sound that proves nearly impossible to track down.

You may be surprised by the number of automotive problems you can troubleshoot simply by listening to the noises coming from your car. In this article, we'll provide a quick overview of the most common. While the following guide may not help you diagnose a failing alternator or catalytic converter, it will shed light on many other issues.

Screeching From Beneath The Hood

You turn the key in the ignition, hear your engine roar to life, and then hear a high-pitched screeching. The problem may be due to a loose drive belt. Long ago, most vehicles had several belts that powered various accessories and components. For example, your water pump had a belt; your alternator had a belt; your air conditioner had a belt; and your power steering pump had a belt.

Today, most vehicles are built with a single serpentine belt that powers these and other components. If it becomes loose, it can slip from its position. This causes screeching.

Hissing From Beneath The Hood

Hissing is relatively easy to troubleshoot. Nine out of ten times, the culprit is a cracked or loose hose. Your vehicle's cooling system - notably, the radiator - is supported by several of these hoses, which are made of rubber. Over time, the rubber deteriorates, and begins to crack. When this occurs, you'll hear hissing.

Because these hoses support the cooling system, they are critical to your engine's health. Fortunately, they're relatively inexpensive and easy to replace.

Pinging In The Engine

This is a problem that can be triggered by several factors. First, the octane of the fuel in your engine may be too low, leading to erratic or late ignition. Second, poor ignition timing can cause pinging. This often occurs when one or more spark plugs fire too soon. A third factor is your cooling system. If it is failing to control the temperature surrounding your engine, the rising heat can cause this sound.

If you hear pinging, use fuel with a higher octane rating. Also, check the coolant level and its temperature (look at the coolant gauge). If the level is fine, but the temperature is higher than normal, have a mechanic inspect the cooling system.

Muted Slapping Near The Road

This noise can be frustrating to track down since it only occurs when your vehicle is moving, and tends to disappear when you stop. It's a pulsing sound, similar to a heartbeat. It happens more quickly as you accelerate, and slows down when your speed declines. The problem is usually in the tires.

Occasionally, a foreign object will become caught in the treads, and cause the slapping sound. More commonly, it is caused by a tear or bubble that has developed in the rubber (often, the sidewall). Unless the noise is caused by something caught in one of the treads, the best solution is to replace the tire.

Squealing Or Scraping From The Brake System

If you hear squealing coming from your brakes, don't assume the brake pads have worn down, and need to be replaced. While this might be the case, the squeal can also be caused by vibrations, even with new brake pads. Have them inspected to make sure they are in good condition. If they are worn, replace them.

A scraping or grinding noise suggests an immediate problem. The sound typically occurs when worn brake pads rub against the rotors. The pads definitely need to be replaced. But if you wait too long, you'll risk allowing the rotors to become damaged. Replacing them is far more expensive.

Learn to recognize the noises your vehicle makes. If you notice any that are unusual, use the guide above to track down the root cause.