The Mercedes-Benz M112 engine series marked a significant shift in the company’s engine design philosophy, replacing the inline 6-cylinder M104 E32 with a more compact and efficient V6 configuration. Introduced in 1997, the M112 family encompasses various displacements and applications, with the M112 E32 being a prominent member. This engine not only delivered a smooth and responsive driving experience but also laid the groundwork for future Mercedes-Benz V6 powertrains.
This article delves into the details of the Mercedes M112 E32 engine, exploring its specifications, common issues, and overall reliability, providing a comprehensive overview for enthusiasts and those seeking information about this robust Mercedes-Benz powerplant.
Technical Specifications of the Mercedes M112 E32 Engine
Manufactured at the Stuttgart-Bad Cannstatt plant, the Mercedes M112 E32 engine was produced from 1997 to 2015, showcasing its longevity and adaptability across various Mercedes-Benz models. Its design features a lightweight aluminum cylinder block and cylinder heads, contributing to reduced engine weight and improved thermal efficiency.
Here’s a detailed breakdown of the M112 E32 engine specs:
| Feature | Specification |
|---|---|
| Manufacturer | Stuttgart-Bad Cannstatt Plant |
| Production Years | 1997-2015 |
| Cylinder Block Material | Aluminum |
| Cylinder Head Material | Aluminum |
| Fuel Type | Gasoline |
| Fuel System | Fuel Injection |
| Configuration | V |
| Number of Cylinders | 6 |
| Valves per Cylinder | 3 |
| Valvetrain Layout | SOHC |
| Bore (mm) | 89.9 |
| Stroke (mm) | 84.0 |
| Displacement (cc) | 3199 |
| Engine Type | Four-stroke, Naturally Aspirated |
| Compression Ratio | 10 |
| Power (hp) | 190/218/224 (various models) |
| Torque (lb ft) | 199/229/232 (various models) |
| Firing Order | 1-4-3-6-2-5 |
| Engine Oil Weight | 0W-30 to 15W-50 |
| Engine Oil Capacity (liter) | 8.0 |
| Oil Change Interval (mile) | 6,000 |
The M112 E32 engine employs a 90-degree V6 configuration, a design choice that facilitated component sharing with the V8 M113 engine, streamlining production and maintenance. It features a balancer shaft to minimize vibrations inherent in V6 engines, ensuring smooth operation. The engine utilizes a Single Overhead Camshaft (SOHC) design with three valves per cylinder (two intake, one exhaust) and hydraulic lifters, optimizing efficiency and reducing maintenance needs. While it relies on a timing chain for durability, it does not incorporate variable valve timing. A variable geometry intake manifold is present to optimize air intake across different engine speeds, enhancing both low-end torque and high-end power.
Common Problems and Reliability of the M112 E32 Engine
Despite its robust design and reputation, the Mercedes M112 E32 engine is not without its potential issues. Understanding these common problems is crucial for maintenance and ensuring the longevity of this Mercedes V6 engine.
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High Oil Consumption: A prevalent issue in M112 engines, high oil consumption is frequently attributed to worn valve stem seals. As these seals degrade, oil can leak into the combustion chamber, leading to increased oil consumption and potentially blue exhaust smoke. Another contributing factor can be issues with the crankcase ventilation system, which, if contaminated or blocked, can also lead to higher oil consumption.
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Oil Leaks: Oil leaks are another common concern. A known weak point in the M112 E32 is the seal of the oil heat exchanger. Over time, this seal can degrade and leak, requiring replacement to prevent oil loss and maintain engine lubrication.
While these issues are noteworthy, regular maintenance, including timely oil changes and addressing leaks promptly, can significantly mitigate these problems and ensure the continued reliability of the Mercedes M112 E32 engine.
M112 E32 Engine Modifications and Applications
The M112 E32 engine saw several modifications throughout its production run, tailored to specific Mercedes-Benz models. These modifications primarily focused on power output to suit the characteristics of each vehicle.
Here are some notable M112 E32 modifications:
- M112.940 (1997 – 2003): Producing 218 hp, this version was used in models like the Mercedes-Benz CLK 320 C208.
- M112.941 (1997 – 2002): Slightly more powerful at 224 hp, this variant powered the Mercedes-Benz E 320 W210.
- M112.942 (1997 – 2005): Similar to the M112.940, this version was specifically for the Mercedes-Benz ML 320 W163.
- M112.944 (1998 – 2002): The 224 hp version for the Mercedes-Benz S 320 W220.
- M112.951 (2003 – 2015): A lower output version with 190 hp for commercial vehicles like the Mercedes-Benz Vito 119/Viano 3.0 W639.
The M112 E32 engine found widespread application across a range of Mercedes-Benz vehicles, including:
- Mercedes-Benz C 320 W203
- Mercedes-Benz CLK 320 C208 & C209
- Mercedes-Benz E 320 W210 & W211
- Mercedes-Benz ML 320 W163
- Mercedes-Benz S 320 W220
- Mercedes-Benz SL 320 R129
- Mercedes-Benz SLK 320 R170
- Mercedes-Benz Viano/Vito W639
Conclusion
The Mercedes-Benz M112 E32 engine stands as a testament to Mercedes-Benz’s engineering prowess in V6 engines. Replacing the older inline-six with a more modern and compact design, the M112 E32 delivered a blend of performance and refinement. While it has some known issues like oil consumption and leaks, its robust construction and widespread use across numerous models underscore its reliability. The M112 E32 paved the way for future Mercedes V6 engines, eventually succeeded by the M272 KE/DE 35 engine, but remains a significant and respected engine in Mercedes-Benz history.
