Mercedes E63 AMG M157
"Currently getting a new timing chain and tensioner from mildly extended crank time, at approx 70k miles. Not cheap but better than finding out the hard way."
Power Variants
Recommendation
The hp figure alone does not indicate reliability risk on the M157. All variants share the same block, timing chain design, and known failure points, the differences are ECU tuning and, on the S model, some cooling and driveline hardware. Buying decisions should be based entirely on documented oil change history and evidence of timing chain condition, not on whether the car is a base, Performance Package, or S variant. A high-mileage 518 hp car with full service records is a safer buy than a low-mileage 577 hp S with gaps in its history.
Known Issues
Timing Chain Stretch and Tensioner FailureCRITICAL
The M157 timing chain and tensioners are known to wear and stretch prematurely, particularly when oil changes are delayed or the engine is started cold and revved quickly. Extended crank times are an early warning sign. Failure to address this can lead to catastrophic engine damage.
Engine Oil Leaks (Front and Rear Seals)HIGH
Multiple forum reports confirm oil leaks on the M157, particularly from the front of the engine. Valve cover gaskets, camshaft seals, and front main seals are common culprits. Oil leaks can lead to scoring if left unaddressed.
Engine Scoring from Oil StarvationHIGH
The M157 and related M278 platforms have shown instances of engine cylinder scoring, particularly on heavier vehicles. This is associated with oil quality degradation or extended oil change intervals. Once scoring occurs, the repair cost is severe.
Camshaft Position Sensor FailureMODERATE
The camshaft position sensors on the M157 are a known fault point, widely reported in the community. Failure can cause rough running, misfires, or a no-start condition. Replacement is relatively affordable compared to other M157 issues.
Spark Plug Wear and Indexing RequirementsLOW
Forum discussions highlight that spark plug replacement on the M157 requires careful indexing for optimal performance. Incorrect installation can cause running issues. Labour access is difficult given the engine layout.
Buying Checklist
Service Reality
Strong Points
Also Found In
Time Bomb Parts Inspect Proactively
Tuning Risk If This Example Has Been Modified
HIGHAn ECU tune on this platform can generally be reverted to a stock-reading file, so a clean scan is not proof the car was never tuned.
Specialist guidance for this exact engine is unusually direct: aggressive tunes on high-mileage examples should specifically be avoided unless the internal components (pistons, ring lands) have been upgraded first, given the known cylinder scoring risk concentrated near the turbochargers. A conservative tune paired with colder spark plugs is treated as comparatively low-risk, while a car chasing large power gains without matching internal work, particularly on a high-mileage example, is running directly into a well-documented, specific, and catastrophic failure mode. Separate from tuning, confirming whether an early (2011-2012) production car received the timing chain tensioner/check-valve fix is an important, tuning-independent check given the lack of a formal recall.
This profile reflects consensus from MBWorld.org, MBClub UK, and specialist technical write-ups (Go-Parts.com, 8020 Automotive, Mercedes Assistance), not manufacturer-confirmed limits. Cylinder scoring rates and the precise mileage/tuning threshold at which risk rises meaningfully are not manufacturer-quantified, and multiple sources describe the M157 as generally more durable than its naturally aspirated M156 predecessor despite these documented weak points. Treat any suspected tuned or previously tuned example as needing a full pre-purchase inspection (compression/leak-down test, misfire diagnosis including camshaft position sensor oil intrusion check, cold-start listen for chain noise on early production cars, and spark plug condition) rather than relying on an OBD scan alone.
Buying Advice
The Mercedes M157 is a spectacular engine that demands respect and meticulous maintenance. Buy one with poor service history and you are inheriting someone else's time bomb. Timing chain issues can appear before 100,000 km and oil leaks are common, so factor in a significant maintenance buffer of at least €3,000-5,000 post-purchase. Only buy from a seller who can provide proof of regular short-interval oil changes and ideally evidence of timing chain inspection or replacement. This engine rewards informed, committed owners and punishes anyone who treats it like a normal car.
Community Sentiment
Mixed to cautious. Enthusiasts love the performance but consistently warn about timing chain vulnerability, oil leaks, and the high cost of any major repair. The consensus is that a well-maintained example is rewarding, but a neglected one is a financial disaster.
Frequently Asked Questions
❯Is the M157 reliable?
The Mercedes E63 AMG M157 has a reliability score of 47/100, rated "RISKY". Fast, expensive, and unforgiving to neglect
❯What problems does the M157 have?
The most frequently reported issues are Timing Chain Stretch and Tensioner Failure, Engine Oil Leaks (Front and Rear Seals), Engine Scoring from Oil Starvation, Camshaft Position Sensor Failure, among others. See the Known Issues section above for symptoms, affected mileage, and repair costs.
❯Does the M157 have timing chain stretch and tensioner failure problems?
Yes, this is a documented issue on the M157, typically appearing around 70,000-130,000 km. The M157 timing chain and tensioners are known to wear and stretch prematurely, particularly when oil changes are delayed or the engine is started cold and revved quickly. Extended crank times are an early warning sign. Failure to address this can lead to catastrophic engine damage. Typical repair cost: €2,500-6,000. DIY difficulty: Expert only.
❯Does the M157 have engine oil leaks (front and rear seals) problems?
Yes, this is a documented issue on the M157, typically appearing around 80,000-160,000 km. Multiple forum reports confirm oil leaks on the M157, particularly from the front of the engine. Valve cover gaskets, camshaft seals, and front main seals are common culprits. Oil leaks can lead to scoring if left unaddressed. Typical repair cost: €800-2,500. DIY difficulty: Hard.
❯Does the M157 have engine scoring from oil starvation problems?
Yes, this is a documented issue on the M157, typically appearing around 100,000-200,000 km. The M157 and related M278 platforms have shown instances of engine cylinder scoring, particularly on heavier vehicles. This is associated with oil quality degradation or extended oil change intervals. Once scoring occurs, the repair cost is severe. Typical repair cost: €5,000-15,000. DIY difficulty: Expert only.
❯Does the M157 have camshaft position sensor failure problems?
Yes, this is a documented issue on the M157, typically appearing around 60,000-120,000 km. The camshaft position sensors on the M157 are a known fault point, widely reported in the community. Failure can cause rough running, misfires, or a no-start condition. Replacement is relatively affordable compared to other M157 issues. Typical repair cost: €200-600. DIY difficulty: Moderate.
❯Does the M157 have spark plug wear and indexing requirements problems?
Yes, this is a documented issue on the M157, typically appearing around 40,000-80,000 km. Forum discussions highlight that spark plug replacement on the M157 requires careful indexing for optimal performance. Incorrect installation can cause running issues. Labour access is difficult given the engine layout. Typical repair cost: €300-700. DIY difficulty: Hard.
❯Is the M157 worth buying used?
The Mercedes M157 is a spectacular engine that demands respect and meticulous maintenance. Buy one with poor service history and you are inheriting someone else's time bomb. Timing chain issues can appear before 100,000 km and oil leaks are common, so factor in a significant maintenance buffer of at least €3,000-5,000 post-purchase. Only buy from a seller who can provide proof of regular short-interval oil changes and ideally evidence of timing chain inspection or replacement. This engine rewards informed, committed owners and punishes anyone who treats it like a normal car.
❯Should I buy a Mercedes E63 AMG with the M157 engine?
The hp figure alone does not indicate reliability risk on the M157. All variants share the same block, timing chain design, and known failure points, the differences are ECU tuning and, on the S model, some cooling and driveline hardware. Buying decisions should be based entirely on documented oil change history and evidence of timing chain condition, not on whether the car is a base, Performance Package, or S variant. A high-mileage 518 hp car with full service records is a safer buy than a low-mileage 577 hp S with gaps in its history.
❯What should I check before buying a used M157?
Before buying, check: Cold-start the engine and listen carefully for timing chain rattle in the first 5-10 seconds; Request a full documented service history proving oil changes at or below 10,000 km intervals with approved spec oil; Inspect the front and underside of the engine thoroughly for any signs of oil leaks or fresh sealant; Perform an OBD-II scan for fault codes, specifically targeting camshaft sensor and timing-related codes; Verify the timing chain and tensioners have been replaced or confirm their condition via specialist inspection.
❯How many km will a M157 last?
There's no fixed mileage limit, it depends on maintenance. The parts worth budgeting for proactively are: Timing Chain and Tensioners (70,000-100,000 km), Front Engine Seals and Gaskets (80,000-150,000 km), Camshaft Position Sensors (60,000-120,000 km). Engines that clear these checkpoints with documented maintenance commonly continue well beyond typical ownership periods.
❯How much does it cost to maintain a M157?
Estimated ownership cost is €9,000-21,000 over 3 years depending on maintenance history and whether deferred repairs are inherited at purchase, based on known issues and typical service needs.
❯What is the real-world fuel consumption of the M157?
Owners report real-world fuel consumption of around 14.7 L/100km.
❯What oil should I use in a M157, and how often?
Community-reported real-world usage suggests changing oil every 10,000 km using Mercedes-Benz 229.5 or 229.51, 0W-40 or 5W-40 fully synthetic, often more conservative than the official service schedule.
❯Is it safe to tune or remap the M157?
The M157 is commonly modified, with a high risk level when pushed beyond stock. Typical weak points under tuning: Cylinder walls (Alusil coating) and pistons, Piston ring lands, Timing chain tensioner (early production), Spark plugs and ignition, Low-pressure fuel pump.
❯What other cars use the M157 engine?
The M157 is also found in: Mercedes-Benz S63 AMG (W221/W222), Mercedes-Benz CLS63 AMG (W218), Mercedes-Benz GL63 AMG (X166), Mercedes-Benz G63 AMG (W463), Mercedes-Benz SL63 AMG (R231), Mercedes-Benz ML63 AMG (W166).
❯Why does the M157 have a bad reputation?
Fast, expensive, and unforgiving to neglect The biggest recurring complaint is Timing Chain Stretch and Tensioner Failure. Mixed to cautious. Enthusiasts love the performance but consistently warn about timing chain vulnerability, oil leaks, and the high cost of any major repair. The consensus is that a well-maintained example is rewarding, but a neglected one is a financial disaster.