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Mercedes-AMG M139 2.0 L Turbo Inline‑4 : Performance, Specs & Reliability
The M139 is the world’s most powerful production four-cylinder engine turbocharged with twin-scroll setup, 9.0:1 compression, combined direct + port injection, and handcrafted under the “One Man, One Engine” philosophy by AMG
Introduced in 2019 as the successor to the M133 Engine, it quickly gained recognition as the most powerful series-production four-cylinder engine in the world. With output reaching up to 416 horsepower and 369 lb-ft of torque, the M139 engine powers some of AMG’s most thrilling models, including the A45 S and CLA 45 S.
M139 showcases AMG’s dedication to precision and performance, featuring technologies like twin-scroll turbocharging, roller-bearing turbo shaft, and hand-built craftsmanship under the “One Man, One Engine” philosophy.
Despite its small displacement, this engine delivers power on par with much larger units, offering an exhilarating driving experience while maintaining efficiency. It’s a true example of how modern engineering can redefine performance in the compact performance car segment.
Engine Variants & Specs
| Variant | Power (kW/PS) | Torque (Nm) | Notes |
|---|---|---|---|
| Base | 285 kW (387 PS) | 480 Nm | A 45, CLA 45, GLA 45 since 2019 |
| S‑model | 310 kW (421 PS) | 500 Nm | More aggressive tuning, same core engine |
| M139I (E‑Performance) | 350 kW (476 PS) | 545 Nm | High-output variant in C‑Class hybrid models |
Highlights:
- – 1991 cc, DOHC, aluminum block/head, 9.0:1 CR
- – Twin‑scroll turbo with electric assistance
- – Combined direct + port fuel injection
- – Rev limit ≈ 7,200 rpm
- – All engine blocks rotated 180° for optimal airflow
M139 Engine Reliability
When discussing high-performance engines, reliability is often a primary concern. The M139 engine, despite its high output, has proven to be quite reliable for a performance engine. Mercedes-AMG invested heavily in ensuring this engine could withstand the rigors of daily driving and spirited performance alike.
The engine’s construction features a closed-deck design, forged pistons, and a twin-scroll turbocharger, all contributing to its durability. Regular maintenance and proper care are essential, as with any high-performance engine, to ensure longevity.
M139 engine problems & Owner Insights
| Problem | Symptoms | Diagnosis & Fix |
|---|---|---|
| Turbocharger leaks | Boost lag, whistle, low power | Inspect turbo housing, hoses; replace if worn |
| Elevated oil consumption | Oil dip required between services | Check PCV valve and bores; top up with quality oil |
| Cooling system strain | Overheating after spirited use | Monitor coolant; inspect water pump and thermostat |
| Spark plug or misfire issues | Rough idle or misfire codes | Use OEM plugs; replace early if performance drops |
Learn more about M139’s Typical Issues in the Next Link;
Spark Plug Misfire: Case Study & Solution
Problem Starting Car: Advanced Diagnosis
Cooling Fan Running Full Speed After Turning Engine On
Maintenance & Inspection Guide
- – Oil + filter: Use synthetic MB229.51, every 10,000 mi
- – Check turbo hoses: Inspect at every oil service
- – Monitor oil level: Check between fill-ups, especially after spirited drives
- – Inspect cooling: Pressure test coolant circuit if overheating occurs
- – Regular scan: Watch for misfire, boost, or temperature codes
M139 Engine Oil Capacity
The Mercedes-Benz M139 engine requires approximately 7.0 liters of engine oil with an oil filter change. It’s essential to use high-quality, fully synthetic oil that meets Mercedes-Benz’s specifications to maintain optimal engine performance and longevity.
Which Mercedes Models Are Equipped with the M139 Engine?
The M139 powers some of Mercedes-AMG’s most dynamic and compact models, ensuring that these vehicles offer exceptional performance. Key models equipped with the M139 include:
Mercedes-AMG A 45 S: The flagship hot hatch, offering blistering acceleration and precise handling.
Mercedes-AMG CLA 45 S: A stylish compact sedan with the heart of a performance car, delivering thrilling performance in a more refined package.
Mercedes-AMG GLA 45 S: Combining the power of the M139 with the versatility of a compact SUV, this model offers both performance and practicality.
Mercedes-AMG GLB 45 S: Another SUV variant, the GLB 45 S provides a bit more space while still delivering the thrills expected from an AMG.
Is the M139 hand built?
Yes, the Mercedes M139 engine is hand-built. Each M139 is assembled by a single AMG technician in accordance with Mercedes-AMG’s “One Man, One Engine” philosophy. This approach ensures that each engine receives meticulous attention to detail, contributing to the engine’s exceptional performance and reliability.
After assembly, the technician signs a plaque that is affixed to the engine, symbolizing the craftsmanship and quality control that goes into each unit.
What is the most powerful Mercedes 2.0 engine?
The most powerful 2.0-liter engine currently offered by Mercedes-Benz is the M 139 engine. It is used in high-performance AMG models like the Mercedes-AMG A 45 S and CLA 45 S, delivering up to 416 horsepower and 369 lb-ft of torque. This makes it the most potent 2.0-liter four-cylinder engine in Mercedes’ lineup, showcasing advanced engineering and turbocharging technology to achieve exceptional power and performance.
What is the max rpm of the M139 engine?
The Mercedes M139 engine has a maximum engine speed (RPM) of 7,200 RPM. This high RPM capability is part of what allows the M139 to produce its impressive power output, contributing to its reputation as a high-performance engine.
What is the boost level of the M139?
The Mercedes-Benz M139 engine, particularly in its high-performance AMG variants, is known for its impressive boost levels. The engine produces different boost levels depending on the model and state of tune:
- – Mercedes-AMG A45 S / CLA45 S (421 hp variant): The M139 in this configuration runs at a peak boost pressure of approximately 2.1 bar (around 30.5 psi).
- – Mercedes-AMG A45 / CLA45 (387 hp variant): This slightly less powerful version of the M139 engine has a peak boost pressure of around 1.9 bar (around 27.6 psi).
These boost levels contribute to the M139 engine’s reputation as one of the most powerful four-cylinder engines in production.
What turbo is on the M139 engine?
The Mercedes-AMG M 139 is equipped with a twin-scroll turbocharger. This turbocharger is specifically designed by BorgWarner and is tailored to optimize both power output and response for the high-performance demands of the M 139 engine.
Key features of the turbocharger on the M139 include:
- – Twin-Scroll Design: This design allows for better exhaust gas flow, reducing turbo lag and improving efficiency. The twin-scroll configuration separates the exhaust pulses, improving the turbine’s response and allowing for higher boost pressure.
- – Roller Bearing Technology: The turbocharger uses a low-friction roller bearing, which further enhances response and efficiency compared to traditional journal bearing turbos.
- – Electronic Wastegate: The turbocharger is equipped with an electronically controlled wastegate, which allows for more precise control of boost pressure, optimizing performance across different driving conditions.
This turbocharger plays a crucial role in enabling the M139 engine to achieve its high power outputs while maintaining strong performance across the rev range.
Conclusion
The Mercedes-Benz M 139 engine is a marvel of modern engineering, offering exceptional performance in a compact package. While it does have some potential issues, with proper care and maintenance, it can provide a thrilling and reliable driving experience.
Whether you’re considering a vehicle equipped with this engine or are simply curious about its capabilities, the M139 engine continues to set the standard for what a four-cylinder engine can achieve.
Frequently Asked Questions
Is the M139 reliable?
Yes, it’s robust for an AMG engine, but maintenance is key: watch oil, cooling, and turbo components.
What makes the M139 special?
It’s hand-built, twin-scroll turbocharged, with dual injection, rotation-optimized intake, and high revs world’s most powerful 4‑cyl.
How much boost does it run?
Peak boost ranges from ~1.9 bar (base) to 2.1 bar in the S‑model.
Do owners experience oil consumption?
Yes, moderate oil top-ups between services are common monitor and use recommended oil.
