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Mercedes-Benz E 350 BlueTEC Problems - How To Troubleshoot And Fix

With a focus on improved gas emissions and overall cleaner technology, Mercedes-Benz has paved the way to key innovations. One of them is BlueTEC, a technology that improves diesel car emissions with a variable-vane turbocharger and the brand's proprietary AdBlue liquid solution. This solution converts harmful nitrogen oxide to nitrogen and oxygen, resulting in a similar performance to gas-powered vehicles with cleaner emissions. One popular BlueTEC model is the Mercedes-Benz E 350.

BlueTEC is well-deserving of its long-standing reputation as a clean diesel powerhouse, as Mercedes-Benz was responsible for inventing the first diesel-powered car engine, followed by the turbo diesel.

Note, in 2018, Mercedes-Benz discontinued diesel vehicle production in the U.S, but many remain in circulation today. It continues to be a fan favorite for people who want equal or superior performance over gas-powered counterparts. 

Keep reading to learn more about what Mercedes-Benz BlueTEC technology is, how BlueTEC works, common problems with Mercedes-Benz BlueTEC, and how to fix these common problems.


What is Mercedes-Benz BlueTEC, and How Does BlueTEC Work?

Developed by Mercedes-Benz, BlueTEC is a technology helping diesel engines gain greater efficiencies without sacrificing horsepower, torque, fuel economy, and other performance indicators. Its proprietary liquid solution, AdBlue, consists of a mix of urea and deionized water. It is added into the engine's exhaust stream and runs through the catalytic converter to convert nitrogen oxide emissions to hydrogen and water vapor, which is completely safe and already present in the air.

Over the years, different iterations of AdBlue have focused on improving BlueTEC for even better torque output and fuel economy. It also works to smooth out ride vibrations using a chain-driven balance shaft.


Common Problems with Mercedes-Benz BlueTEC

Issues with Diesel Particulate Filter

Your Mercedes-Benz E 350's particulate filter is responsible for trapping soot, which the exhaust gas then burns at blistering hot temperatures regulated by your engine computer. If there is an issue with your engine (e.g., faulty EGR valve or temperature sensor), it may compromise this burning of soot particles.


Burned Out Diesel Exhaust Fluid Heater

Your Mercedes-Benz E 350 uses AdBlue to convert nitrogen oxide emissions to hydrogen and water vapor. It is stored in a tank, warmed by an electric heater to regulate temperature. In extremely cold weather, the electric heater can lose effectiveness, causing your DEF heater to freeze. Do-it-yourselfers can purchase a replacement DEF heater.


Limp Mode

Limp mode occurs when your Mercedes-Benz E 350 's engine loses power. Potential causes of limp mode include turbocharger actuator leaks, a defective EGR valve, or a broken swirl flap motor. As a result, power reduces to lower priority components, such as the air conditioner.

There are many factors that could cause the Mercedes-Benz E 350 to go into limp mode, including transmission wiring issues, defective engine parts, faulty engine sensors, dysfunctional brakes, faulty brake system wiring, and engine wiring defects. The check engine light will bring all of these issues to the driver's attention. For a quick diagnosis, we recommend using an OBD-II diagnostic scanner.

You can resolve many of these Mercedes-Benz E 350 limp mode issues on your own without visiting a licensed Mercedes-Benz technician or dealership.


Hardened Oil Cooler Gaskets

Hardened oil cooler gaskets on your Mercedes-Benz E 350 can cause excess oil leaks from your oil cooler. It's a hard issue to solve, requiring the extraction of your turbocharger and intake manifold. Expect stalling, spluttering, and drops in your overall fuel economy.

Oil leaks can also be present in different areas, such as your oil filter, turbocharger, or oil pan.


Worsening Fuel Economy

A drop in your Mercedes-Benz E 350's fuel economy could be indicative of an issue with your Mercedes-Benz BlueTEC diesel.


How Do I Diagnose and Fix Mercedes-Benz E 350 BlueTEC Problems?

When your Mercedes-Benz E 350's Check Engine Light turns on or upon sensing a problem, we recommend purchasing a Mercedes-Benz OBD-II scanner, which plugs into your OBD-II port to produce a series of diagnostic codes that pinpoint the issue. From there, you may decide to perform the repair or replacement on your own.