1991 Mercedes-Benz 420SEL Vibration Diagnosis Cost

Sometime, in every vehicle, vibrations will be felt inside the cabin. Momentary vibrations after a stop, or vibrating as the vehicle starts is normal, especially in older vehicles. However, if persisting vibrations exist, the vehicle may need service.

Whether the driveshaft, engine, transmission, or wheel, vibrations can come from almost anywhere on the vehicle. As components of the vehicle wear with age and mileage, they slowly wear away at each other. Over time, this wear leads to play, or looseness, between components, and when those components are placed under force, vibrations occur. Also, padding materials, meant to reduce vibrations and noise, wear out over time, and when they stop dampening vibrations, the entire vehicle is subject to them.

Some component failures will illuminate the check engine light, and some will not. Constant vibrations originating from poor running conditions in the engine or transmission will generally be accompanied by the check engine light. However, vibrations from the driveshaft, axles, wheel bearings, improper wheel balance, improper wheel alignment, and worn suspension components are not commonly associated with the check engine light, and tend to cause issues only while the vehicle is moving at speed. The vibration can also be joined later by a grinding, howling, or squeaking noise, that changes in pitch with the change in vibrations.

Driving with a slight vibration is generally acceptable, however, if the vibration turns to grinding or rattling, the vehicle should be taken out of service until repaired. Vibrations of interior panels do not generally prevent the vehicle from operating in any way.

Even brand new vehicles come back to the dealership with squeaks, rattles, vibrations, noises, electrical issues, and leaks. These items can happen any time on a vehicle, but they tend to occur in the first 25,000 miles, and after 125,000 miles most frequently. The age of a vehicle does influence the amount of vibration issues it may encounter, since most components on the vehicle slowly degrade with time.

Diagnosing a vibration can prove to be difficult, especially if the vehicle only vibrates under specific conditions, or, worse yet, the vehicle vibrates randomly. These vibrations are typically associated with the engine, and can be identified through connecting an computerized scanning tool, and monitoring the conditions in the engine as the vehicle vibrates. This will give a trained technician an understanding of why the vehicle is vibrating, to which they must apply classroom training and experience to identify the responsible component. If the engine and transmission are functioning properly, the engine and transmission mounts will be inspected, and failure will require replacement. If the vibration only occurs as the vehicle is moving, the technician will conduct a test drive and visual inspection of the vehicle. The suspension and driveline are inspected for worn or broken components, and in some situations, the wheels may be balanced and rotated.

Engine vibrations can come from a variety of sources, and repairs could range from a few minutes to many hours. Some vehicles are known for vibration issues that can arise from the slightest shift in a motor mount, and some have a reputation for the engine balance shaft failing. Both of these cause a fairly strong vibration, but the solution to one can be replacing the engine, and the solution for another is a small adjustment. In many cases the ignition system, engine and transmission mounts, and vacuum leaks are responsible for the vibrations, and servicing or replacing worn components typically restores the vehicle to proper operation.

Using a properly certified technician for diagnostic work can dramatically reduce diagnostics cost. The hourly rate may be higher, but the time spent in diagnostics will generally be much shorter. Also, a diagnosis from an ASE certified technician will be proven, and reached through testing, so they will not waste your hard-earned money replacing parts until the solution is stumbled upon. Lastly, many shops do not charge different diagnostic rates for all types of diagnostics. This results many times in a specific diagnosis being billed as general diagnostics.

Many spark plugs, engine mounts, and transmission mounts have been needlessly changed when a vibration is noticed in the vehicle. We only recommend changing these components if they are diagnosed as faulty, or if changing a component is a specified step required by a diagnostics platform.

Repairing a vibration will vary in difficulty and skill level. Vibrations caused by simple items, such as the idle air control valve or spark plugs, can be handled by most handy people. Technicians are required, however, when a diagnosis cannot be reached, when there is not enough information without professional scanning equipment, or when the repair is outside of the capabilities of the DIYer.