M157 Engine
If you’ve ever driven or heard a Mercedes-AMG vehicle roar, there’s a good chance it was powered by the M157 engine. This hand-built 5.5-liter biturbo V8 engine redefined modern performance for AMG models, delivering immense power with advanced efficiency.
The M157 blends raw muscle with cutting-edge German engineering, making it one of the most exciting engines of the last decade. But like any high-performance powertrain, it has its fair share of pros, quirks, and concerns.
Let’s dive into the M157’s strengths, specifications, and known issues to help you understand what makes this engine special and what to watch out for.
M157 Engine Reliability
The M157 is generally regarded as a reliable engine especially when maintained properly. It uses forged internals, advanced direct injection, and twin turbochargers, offering a blend of longevity and performance.
That said, this engine isn’t low maintenance. It thrives on high-quality oil, timely servicing, and careful driving habits. Owners who follow Mercedes-Benz’s recommended service schedule and avoid aggressive cold starts often enjoy trouble-free performance well into high mileage.
However, the M157 engine is not without its weaknesses. Components like the timing chain system, camshaft adjusters, and valve cover gaskets have been known to fail over time, especially in vehicles with inconsistent maintenance histories.
Despite this, many enthusiasts consider the M157 more reliable than its predecessor (the naturally aspirated M156) due to improvements in torque delivery and internal efficiency.
M157 Engine Specifications: Raw Numbers, Refined Output
- Engine Type: 5.5-liter V8 Biturbo (Bi-Turbocharged)
- Configuration: 90-degree V8, DOHC
- Fuel System: Direct Injection with Piezo injectors
- Bore x Stroke: 98.0 mm × 90.5 mm
- Compression Ratio: 10.0:1
- Power Output: 518–577 hp (depending on model)
- Torque: 516–664 lb-ft
- Turbochargers: Twin water-cooled turbos with air-to-water intercooling
- Redline: Around 6400 RPM
- Transmission Pairing: AMG SPEEDSHIFT MCT 7-speed transmission
The M157 produces impressive low-end torque, offering explosive acceleration and effortless highway cruising. Models equipped with the optional AMG Performance Package crank power up to 577 horsepower and 664 lb-ft of torque.
M157 Oil Capacity
The M157 engine requires a significant volume of oil to properly lubricate its high-performance components. The oil capacity for the M157 is approximately 8.5 liters (about 9.0 quarts), including the oil filter.
Using high-quality synthetic motor oil that meets Mercedes-Benz’s 229.5 specification is essential for maintaining engine health and performance. Regular oil changes are especially critical for the M157 due to the high temperatures and stresses placed on the engine during spirited driving.
Skipping oil changes or using the wrong oil type can accelerate wear on the turbos and internal components. For best results, follow the service interval recommended by Mercedes or shorten it under heavy usage conditions.
Common M157 Engine Problems: What to Watch Out For
Timing Chain and Camshaft Adjusters
Over time, the timing chain may stretch, leading to rough idling or check engine lights. The camshaft adjusters may also become noisy or fail altogether, requiring labor-intensive repairs.
Valve Cover Oil Leaks
Oil seepage from the valve covers is a known issue, particularly in higher-mileage engines. While not catastrophic, it can lead to mess and oil consumption if ignored.
Coolant Hose Failures
The coolant hoses routed between the turbos and intercooler can develop leaks or cracks over time due to high heat cycles. Replacing them with upgraded versions can prevent future failures.
Turbocharger Issues
Although the turbos are generally durable, some owners report failures after 100,000 miles usually due to oil starvation or overheating. Proper cooling and oil maintenance help mitigate this.
Carbon Build-Up
Like many direct-injection engines, the M157 can suffer from carbon deposits on intake valves, leading to performance loss. Walnut blasting or chemical treatments may be necessary periodically.
Learn about a case study in Mercedes ML Equipped with M157 Engine in the following article
Engine Check Light Was On: Here’s What Really Caused It
What Cars Have the M157 Engine?
The M157 engine was used in a wide range of AMG models between 2011 and 2019, including:
Mercedes-Benz E63 AMG (W212)
Both sedan and wagon variants, offered with RWD and 4MATIC.
Mercedes-Benz CLS63 AMG (W218)
A performance version of the stylish four-door coupe.
Mercedes-Benz S63 AMG (W221 and early W222)
Luxurious performance in a flagship sedan package.
Mercedes-Benz CL63 AMG (C216)
Grand touring coupe with twin-turbo torque.
Mercedes-Benz G63 AMG (W463 pre-2018)
Iconic boxy SUV with an aggressive V8 soundtrack.
Mercedes-Benz ML63 AMG (W166)
High-performance SUV combining luxury and brute force.
Mercedes-Benz GL63 AMG (X166)
A three-row powerhouse for family thrill seekers.
Mercedes-Benz SL63 AMG (R231, pre-facelift)
A convertible blend of performance and open-air luxury.
Conclusion: Should You Own an M157-Powered Mercedes?
If you crave neck-snapping acceleration, deep V8 sound, and aggressive AMG styling, the M157 is an outstanding engine to own. It offers supercar performance with the comfort and practicality of a daily driver provided you’re prepared for its maintenance needs.
Regular servicing, quality oil, and addressing known issues early will ensure the M157 engine rewards you with thrilling performance for years to come.
Whether you’re buying used or already own one, knowing the specs, common problems, and maintenance needs will help you get the most out of this engineering masterpiece.
