Initial Inspection and Diagnostic Overview: Overview

NOISE, VIBRATION AND HARSHNESS
Noise is any unwanted sound, usually unpleasant in nature. Possible sources of noise are the:
- engine.
- intake and exhaust system.
- driveline.
- wind.
- road surface.

Vibration is an unwanted medium-to-high frequency movement that is either regular or random in nature. It may be felt or heard. Possible sources of vibration are the:
- tires.
- engine.
- engine accessories.
- suspension.
- driveline.

Harshness refers to the ride quality and is very subjective. Reference to previous conditions is usually the only way to identify harshness as a symptom.

All vehicles produce some noise and vibration. Four-wheel drive and all-wheel drive vehicles produce different noise and vibration than front-wheel drive and rear-wheel drive vehicles. If drivers are new to a type of vehicle, they may think that some sounds are abnormal when they are normal for that vehicle.