Common Problems on Mercedes-Benz

Mercedes E-class getting Service at RennWerks

22 Feb Common Problems on Mercedes-Benz

Common Problems on Mercedes-Benz

There is a common set of problems that we have often seen on Mercedes-Benz. In this article we will cover problems that we have commonly seen in our workshop on most Mercedes models such as: C-Class, E-Class, S-Class, CLK, SLK, ML, GL, GLK, and CLS.

1. Engine Mounts and Transmission Mounts

Engine Mounts and Transmission Mounts on modern Mercedes-Benz cars are often liquid filled. The purpose of the mounts is to keep your engine and transmission stable and mounted to your MB chassis while preventing vibration from being transmitted to the passenger cabin. In older Mercedes models, these were made of solid rubber and it was really obvious when they failed. You would feel a large kick or thumb when you applied the gas. With the liquid filled mounts, the failure comes on more slowly as an ever increasing vibration in the seat, cabin, and/or steering wheel. Engine and transmission mounts should be inspected regularly at 7 years and after 80,000 miles of age.

2. Steering & Suspension Components

Ball Joints, tie rods, sway bar links, and control arm bushings on Mercedes often start wear out after 5 years of age and/or 60,000 miles.  These items are the anchors of your suspension components and allow them to move with the springs and wheels as you travel across the road surface. Often when your start noticing  excessive tire wear and the wheel and steering alignment no longer feel straight, we often find steering and suspension component failures that need to be addressed first, prior to giving your Benz an alignment.

3. Window Regulators

Window regulators are responsible for raising and lowering the windows on your Mercedes-Benz when you press the window switch. Since the mid 1990s Mercedes has been using plastic pulleys and spools powered by an electric motor to wind a braided metal wire attached to your window for raising and lowering.  Often, it’s the plastic components that fail from age and use and thus require replacement of the window regulator unit. We only see window motor failures occasionally.

4. Air Suspension and AirMatic Components

The S-Class W220 chassis of Mercedes-Benz and later E-Class W211 were the first Mercedes to use AirMatic suspension. The AirMatic suspension system, use air bags in place of regular coil springs on the Mercedes suspension. They are generally built as one unit with the shock absorber or strut and are often referred to as Air Struts. To control the suspension is a complex system of pumps, valves, tubing, and computer controls. We feel badly for customers that have AirMatic failures. The diagnosis is often expensive as well as the parts. Most often we find an air leak at one of the air strut assemblies, but it is not uncommon to find an expensive air pump or control valve unit failure. Surprisingly, actual leaks at the plastic air lines used in plumbing the suspension are uncommon.

5. Transmission Problems

The 722.5 and 722.6 series of Mercedes transmissions are generally tough and robust units as long as they are given a filter and fluid service every 40k – 60k miles. Unfortunately, although the mechanicals are tough, we have often seen valve body failures. Also the wiring harness that connects to the transmission is prone to leaking internally and allows transmission fluid to destroy the harness and the connected transmission computer. These items should be inspected during routine service by a trained Mercedes-Benz technician and can save the customer thousands of dollars if detected early.

6. Check Your Gas Cap

Many check engine light issues are discovered because the Mercedes owner has a slightly loose gas cap. The fuel system on MB cars is supposed to be sealed to prevent fuel vapors from entering the environment. The computers on your Mercedes check for overall system leakage and with trigger a “check engine light” if things don’t seem up to par. Make sure your gas cap is tight after filling up the tank and before starting your car.7. Misfires and Ignition System Problems

7. Misfires and Ignition System Problems

Mercedes-Benz owners often forget that the spark plugs, wires, and ignition coils on their Mercedes are serviceable items. Mercedes recommends replacement at 100,000 miles. Due to experience, we often see failure in the spark plugs and ignition system earlier. Engine misfires are nothing to mess with and should be fixed immediately or risk severe or permanent and costly engine damage. Ignition misfires are noticeable as a rough running engine that lacks power. It is usually unmistakable by the Benz owner when it occurs. We encourage customers to service the ignition at 60k miles on older models and 80,000 miles on models built after model year 2004.

– OUR MISSION –

Performing a regular engine tune-up on your Mercedes-Benz can restore lost power, efficiency, and improve gas mileage. At RennWerks, we are experts at providing the best and tune-up on your engine. It all starts with a comprehensive mechanical and computer systems inspection using our Mercedes-Benz dealer level equipment.

After having a proper tune-up performed on your car, you will notice that your car will run smoother, start up easier, and be more efficient. You will feel that the lost pep of your car may return. A regular engine tune-up using Mercedes factory recommendations and additional items that we regard as prudent can  help prevent costly engine failures and save you money in the long run. “An ounce of prevention is worth a pound of cure.”

When you get car tune-ups based on your vehicle manufacturer’s recommendations, your engine will have lower emissions, improved fuel economy, and restoration of lost power.

Quality and Competence

We are Mercedes-Benz experts. At Rennwerks we provide the best quality OEM parts from manufactures such as Bosch, Mahle,  and Mann. We have expert trained staff that undergo constant training and education to stay up to date with the latest industry technology. We have dealership level equipment. Give us a call!

We take pride in caring for our customers, and are invigorated by the opportunity to provide competent and comprehensive automotive repair services. We strive to be the leading service, repair, tuning, and race facility in the San Jose, Los Gatos, Saratoga, Campbell, Cupertino, Willow Glen, Cambrian, Almaden, Santa Clara, and Evergreen Areas while providing you personalized, detailed, and friendly service. Our relationships are built on trust, communication, integrity, and commitment to our purpose; to be the best shop we can be to you, the customer.

To schedule an appointment for major or minor service, please contact service@rennwerks.com or 408-370-7480. We welcome you to stop by our shop at 1070 Dell Ave Campbell, CA 95008. If you have any questions about your auto’s performance or maintenance, don’t be shy about asking our friendly staff for assistance.