Because the list of potential causes is a long one, don’t jump to conclusions until you’ve performed some preliminary checks.Ī vibration or noise that only occurs when accelerating or coasting typically indicates a problem in the driveline or chassis.Ī vibration or a noise that depends on engine rpm alone should tell you to look in the engine compartment. This will confirm the problem and hopefully give you a clearer picture of what exactly is happening.Ī vibration that appears above a certain vehicle speed should point you in the direction of the wheels, driveline and suspension. Next, take the vehicle for a test drive if possible, and try to duplicate the operating conditions that create the vibration or noise. Focus on the driving conditions that accompany the vibration or sound.ĭoes it only occur under certain driving conditions? If so, when? Does it change with vehicle speed? When is the problem most noticeable? When did the customer first notice the problem? Is it a noise (sound only), vibration or both? Where does the noise or vibration seem to be coming from? Can they feel it in the steering wheel, seat or both?” The point is, don’t get bogged down in the semantics of describing the symptom. That may not be easy because the typical motorist may describe a vibration as anything from a thumping noise to a shudder, rattle or shake. When a customer comes to you with a vibration or noise complaint, the first diagnostic step is to get as accurate a description as possible of what’s happening from your customer. Random - The vibration/noise comes and goes with no obvious connection to engine rpm, vehicle speed or driving conditions. Vehicle speed sensitive - The vibration/noise only occurs at certain speeds or changes in direct proportion to vehicle speed.Īcceleration/deceleration sensitive - The vibration/noise is only noticed when vehicle speed changes (as when starting out from a stop, passing, slowing down or coasting). The symptom appears or changes in direct proportion to engine rpm. Most vibrations and noises can be classified according to when they occur:Įngine speed sensitive - The vibration/noise is directly related to engine speed and nothing else (not vehicle speed or driving conditions).
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