8 Most Common Problems of Mercedes E320

What kind of problems does a Mercedes E320 usually have? We’ve written about Mercedes cars and their problems many times on this blog, so it’s not more than fair to include the E320. This reasonably popular model has been around for a while, making it reasonably easy to identify common problems. These are as follows:

The Mercedes E320 has well-known electrical problems caused by water leaking through the door, sunroof, or trunk. Furthermore, the E320 has bad stabilizer bar bushings that wear out quickly, and the same can be said for the crankshaft position sensor. Rust is a common problem with the older E320 models. Rust can be found on the floorboard, front fenders, and on the bottom side of the doors.

However, that certainly doesn’t say it all. Read on! Below we will discuss each problem in more detail and ensure you’re up to speed.

1. Problem With The Electrical System

Although the E320 is a pretty robust Mercedes Benz vehicle, some models are notorious for recurring electrical problems. While electrical issues can be related to a leaky sunroof in the SLK200, that’s not the case for the E320.

The electrical system on the E320 includes many components which function separately or together. Typically, these electrical systems range from infotainment to transmission control or engine systems. 

Since many of these systems operate independently, the failure of one system is often unrelated to other electrical systems in the car. 

Reportedly, in most cases, water seepage is the main culprit of the electrical problems. Any dripping or leaking water from the door or sunroof can cause an electrical malfunction in the vehicle. As most electrical components run along with the floorboard of the E320, water leakage can make the car’s computers and critical electrical systems go wrong.

Moreover, in a few cases, the Mercedes E320 would lose power due to water leakage in the trunk. If this happens, you will experience less or no power from the engine of your E320. To determine the cause of the problem, open the trunk of your Mercedes by placing the key into the key fob. In case of a severe water leak, you will notice water in the car’s trunk and behind the driver’s seat. 

Watch the video below for a more in-depth explanation of this leak in the E320.

In worst cases, the water seepage can cause the Mercedes E320 to stall completely and would require to be towed down to the service station for repair. The engine stalling problem isn’t completely unique to the E320 and we’ve also seen this problem in the Mercedes W204 as well.

Usually, the repair of any fault in the electrical system caused due to water leakage would require a complete diagnosis which can be pretty expensive in the E320 or any other Mercedes vehicle for that matter.

2. Bad Stabilizer Bar Bushing

On the Mercedes E320, the stabilizer bar bushing is rubber blocks that hold the sway bar or stabilizer bar and secure it to the frame of the vehicle body. Usually, there are two stabilizer bushings on each stabilizer bar of the E320, held in place by the bushing brackets. 

The primary function of the stabilizer bushings and the bushing brackets is to secure the stabilizer bar in place when under torsion from the vehicle’s weight.

The sway bar (or stabilizer bar) on the E320 is used to combat vehicle rolling. While taking a turn, the vehicle leans or rolls, placing more pressure on the outside tires and less on the inside tires. This variation in weight impairs vehicle handling and traction.  

The stabilizer bar bushings can wear out quickly over time. Especially on Mercedes E320s with high mileage, this problem is common. 

When the bushing goes wrong, it usually causes squeaking noise when the car drives over bumps or takes a turn. Depending on where the sound is coming from, you can detect bad bushings on either front or rear of the vehicle. Also, the squeaking noise would generally increase over time as the wear in the bushings worsens. 

Although you can drive your Mercedes E320 if the stabilizer bar bushings have started to wear out, this is not recommended. In worst cases, severely damaged or worn-out bushings can expose the stabilizer bar to come into metal-to-metal contact with the bushing brackets, leading to further damage to the stabilizer bar or brackets.

Solving this problem would require the replacement of the stabilizer bar bushings on your Mercedes E320. Being an inexpensive part, you can easily get the bushings for under $30, while the average total cost of replacement can vary from $200 to $250, including additional labor costs. Watch the video below to understand how to replace the stabilizer bar bushings.

Since there is no fixed replacement schedule for the stabilizer bar bushings, most models of the E320 need to have them replaced at some point. It is a good idea to watch for these two significant symptoms to identify any fault with your stabilizer bar bushing – 

Squeaking, Knocking, Grinding, or Clunking Noises –The most common symptom of bad bushings is when you notice any unpleasant noise coming from near the vehicle’s suspension. The type of noise you detect can help detect the location and extent of the stabilizer bar bushing failure. A complete bushing failure will cause metal-metal contact; in that case, you might hear a grinding or clunking noise. 

While if the bushing is complex or has dried out, you might hear a squeaking noise. 

Visible Physical Damage: During visual inspection, the stabilizer bar bushings are cracked, worn out, loose, dislodged, scuffed, or even missing.  

Besides these indications, it is good to replace the stabilizer bar bushings if you replace the sway bar links at any point.

3. Leaking Sunroof

One of the most common problems with a Mercedes E320 is that the sunroof roof has some leaking problems. The most logical explanation is that the rubber seals that prevent water leaks have given out. 

Many people experience a wet floorboard after heavy rain by the sunroof in the Mercedes E320. The main reason behind this is that two drain holes are located on the side of the sunroof, which drain the water out, but sometimes these holes get clogged. 

As the leaking sunroof seems a common problem in the E320, This could be a design defect. Therefore it is advisable to check the carpets of the passenger seats to see if it feels moist. If it does, this indicates a leaking issue that most likely has to do with the roof—this needs to be treated as it can also do some electrical damage to the car.

4. Faulty Crankshaft Position Sensor

It is a commonly observed problem in the earlier models of Mercedes Benz E320. This problem generally results in unexpected halting while driving.

The Crank Shaft Position Sensors are used to determine the car’s crank’s position and/or rotational speed (RPM). If there are some issues with the crankshaft position sensor or its wiring, the crankshaft signal causes the engine to cut off while it is still running, which results in stalling the engine. It is usually an indication of a wiring problem. However, a bad crankshaft position sensor can also produce this same problem.

The four most common symptoms of a faulty crankshaft position sensor:  

• The engine light is blinking
• Difficulties starting the vehicle
• The vehicle is stalling and/or backfiring
• The engine is making the vehicle vibrate

The cost of repairing or replacing the Crankshaft Position Sensor in the Mercedes E320 can vary from $150 to $250, depending on the need. Watch the video below to see how to replace this sensor on the E320.

5. Problem With The Key And Ignition

Mercedes owners experience this faulty ignition problem more often than other drivers. This problem occurs mainly due to the complex electrical systems and theft-deterrent features specially designed to protect your Mercedes.

If you insert the key into the ignition of your Mercedes-Benz, but nothing happens. Mercedes Benz ignition key problems may include the key not turning in on ignition, the car not starting, and issues inserting and removing keys. 

The most common cause is a dead or a dying battery, but this isn’t the only reason several other problems can be described as failed Electronic Ignition Switch or EIS, faulty shifter module, or a lousy steering wheel module.

What are the common issues of Ignition and Key?

Issues with Key: These are the possible reasons your key does not turn in on ignition- when the key is bent, if the key is broken, or has damaged teeth due to excessive wear and tear. 

Related Component Issues: There are many components of a vehicle that are related to the ignition system. One of the components is that the locked steering wheel can be why your key won’t turn in the ignition. 

Dead or Dying Battery: It can also be a cause for your Mercedes E320. This higher-end vehicle has advanced electronic ignition systems, and without the needed power flowing through its system, the key will not turn. 

Ignition lock cylinder issues: It can happen due to the dirtiness in the ignition lock mechanism; the dirty key can cause it. It results in the ignition lock pins not lining up correctly with the key. 

6. Rusting Parts

We all know that cars generally face rust issues due to the lack of usage, but the Mercedes E320 has been known to rust out easily and quickly, not even on older or used cars but even on newer cars. What is just as surprising is identifying how many areas the vehicle can get rust on.

Rust has been observed on the Mercedes E320’s floorboards, beneath the wheel wells, on the bumpers, front fenders, underneath the driver’s and passenger’s seats, at the bottom of the doors, and even behind the license plate.

How Can You Protect Your Mercedes From Rusting?

Anti-Rust Solution: It helps prevent your car from rusting or provides permanent protection against corrosion. The solution needs to be applied in the sash area of the door panels. 

Sealing Cover: It is fixed on the inner side of the door; it can be easily removed or placed. It prevents rust by stopping the water from entering through the door panel. 

Undercoating: The bottom of the vehicle is constantly exposed to gravel, sand, silt, and other debris found on the roads. It protects the bottom of the car from flying stones and increases the vehicle’s life cycle by preventing corrosion. 

7. Issues With The Transmission System

Are you facing problems with your Mercedes transmission? The transmission is essential for your car. It is responsible for shifting the gears and helps the vehicle move forward. If you are facing issues with the transmission, fixing it as soon as possible is advisable to avoid any unavoidable circumstances.

Mercedes is famous for its premier luxury vehicles. Their automatic transmission has continued to evolve and become better each year. Despite this fact, their transmission does have some issues sometimes. Many different problems lead to a failure in transmission. While driving, if you hear any weird noises, you should always get it checked out.

What are the common problems that Mercedes E320 Transmission Has?

Although Mercedes has built a reputation for producing very reliable cars, their transmissions sometimes have issues. It is essential to be aware of some common transmission problems you could face with your Mercedes transmission.

• Less transmission fluid
• Transmission wire harness 13-pin (O-ring) connector oil leak/contamination
• Valve body or conductor plate defective
• It is not coming out of park due to a faulty brake light switch.
• Defective shifter module

Repairing the Mercedes E320 transmission is quite expensive. Not only is transmission an essential part of your car’s functioning, but it is also difficult for a mechanic to perform. And if you continue to drive, ignoring these issues, the cost will only increase over time, can range from $1,800 to $5,000.

8. Insulation Wire Damage Issues 

Owners living in the hot regions may have to deal with this issue of the Mercedes E320. In United States terms, think of places like California, Arizona, Texas, etc. The heat emanating from these places significantly affects the car’s harness wiring insulation.

The Mercedes insulation cracks open due to the excessive heat exposure and, eventually, damaging the engine. When the entire state is hot throughout the year, it’s difficult to take precautions to protect your Mercedes-Benz.

Contrary to these facts, heat isn’t the only reason that damages the electrical wires. In fact, both severe cold and hot conditions can crack or damage the wire. 

If the cover on a wire is damaged or torn, it could be sealed with electrical tape to prevent further damage. The average repairing cost can vary from $100 to $400, depending on the condition of the wire and the work required.

Closing Thoughts

The Mercedes E320, while a popular model, comes with its own set of challenges.

Notable among these are electrical problems due to water leakage, premature wear of stabilizer bar bushings and crankshaft position sensors, and prevalent rust issues, especially with older models. I’ve tried to shed light on these recurring problems, examining their causes in detail, to better equip E320 owners or prospective buyers.

But just remember, every vehicle will have problems whether it’s the loud engine of the Mercedes ML350, costly maintenance of a Mercedes Benz, or a transfer case issue with the 4Matic problems will happen.

Always bear in mind these potential issues when pricing an E320 and, as with all used cars, consider investing in a pre-purchase inspection to uncover any hidden problems. With proactive maintenance and informed ownership, you can continue to enjoy the Mercedes E320’s renowned comfort and driving experience.