How to Diagnose Automobile Noisesby eHow Cars Editor
Noises in your car can be scary and annoying, but they can also give you an idea of what the problem is. To diagnose automobile noises, listen carefully to figure out when they occur and what they sound like.
Pinpoint the location of the noise. Noises in the wheels could be brake, tire or wheel problems. Sounds under the hood can be engine, transmission or differential problems. If the noise comes from under the car, it's probably an exhaust system problem.
Distinguish the type of noise in the wheels. Screeching from a wheel when you aren't braking is a sensor letting you know that your brake pads need to be replaced. A squeal when braking signals worn brakes. Clicking from a wheel can be caused by a loose wheel cover or something stuck in the wheel or to the tire.
Determine the type of noise in the front of the car. Differential gear noises make a ringing noise. Howling indicates worn gears. Knocking in the engine could be a worn camshaft, while hissing is a coolant or hose leak. Clicking can be caused by a damaged or loose fan blade or low oil levels.
Figure out whether the noise is coming from under the car. Thumping or rattling could indicate a loose tailpipe or muffler.
Find out whether the noise occurs during acceleration or deceleration. Noise during deceleration could be a loose pinion-bearing preload. If it happens when accelerating, it could mean that something in the differential is worn. A rattle when accelerating could be improper fuel grade, an over-heating engine or an ignition problem. A rasp while accelerating could be a blown exhaust.
See if the noise occurs at certain speeds. At high speeds, a quiet rumble could be worn carrier bearings, and a whirring noise means worn pinion bearings. Howling at a certain speed indicates overloaded gears or lubrication problems.
Think about recent driving or weather conditions. Squealing or screeching is usually a loose or worn belt, but they can squeak after going through water or when humidity is high. Screeching during steering is a power steering belt.