Mercedes-AMG E63 W212

Early M157 engines lacked check valves in the cylinder head oil galleries, allowing oil to drain back overnight. This starves the secondary chain tensioners of oil pressure during startup, causing the chain to slap against guides and accelerate wear. Affected engine serial numbers range from 157 9xx 60 009368 to 017984 (need check valves plus new tensioners) and 017985 to 022333 (need check valves only). When the chain stretches beyond tolerance, fault codes P0017/P0018/P0019 appear with rough running and misfires. All three chains (primary, left bank, right bank) are replaced together along with guides, tensioners, and check valves. An independent AMG specialist charges approximately €3,000-4,000 for the complete job, while a Mercedes dealer quotes €4,500-5,500. This is an interference engine, so a skipped chain causes catastrophic valve-to-piston contact. Post-December 2012 engines have check valves and updated tensioners from the factory. Always verify the engine serial number and whether the check valve retrofit has been completed.

The most critical M156 failure. Factory head bolts are torque-to-yield design that permanently stretches during installation, creating a thin zone vulnerable to corrosion. Affected engines have serial numbers below 60-060658 (roughly up to mid-2011). As bolts corrode and loosen, coolant enters the combustion chamber causing misfires, white exhaust smoke, unexplained coolant loss, and eventually catastrophic engine damage if ignored. Preventive head bolt replacement with updated bolts costs €3,000-5,000 at a specialist (both heads must come off). If engine damage has already occurred, a rebuild runs €6,000-8,000 or more. Aftermarket head studs from companies like Weistec and ARP are popular upgrades. Mercedes issued a TSB but no formal recall. When buying a pre-2011 M156 car, verifying head bolt replacement is the single most important check.

The AIRMATIC air suspension is standard on all W212 E63 AMG models. Over time, the rubber air bladders in the struts develop cracks and leaks, typically after 80,000-120,000 km or 8-10 years. A leaking strut causes the car to sag on one corner, especially noticeable after standing overnight. The air compressor then works overtime to compensate, leading to premature compressor failure as well. A single OEM front strut costs approximately €800-1,000 for the part. A complete front strut replacement including labour runs €1,200-1,800 per corner at an independent shop. Rear air springs are cheaper at €400-600 per side. If both fronts and the compressor need replacement simultaneously, total cost reaches €3,500-5,000. Aftermarket struts from Arnott or Bilstein offer savings of 30-40% versus OEM. This is a near-certainty on high-mileage examples and is the most common expensive repair on any W212.

The internal wastegate flappers develop play over time from constant cycling, producing an audible rattle that sounds like a can of stones being shaken. The noise is most noticeable on light acceleration between 1,800 and 2,500 rpm. Mercedes issued TSB LI09.40-P-061542 but concluded the noise is considered normal for AMG models and the turbochargers should not be replaced. Aftermarket wastegate repair kits with stainless steel bushings and flappers cost €200-400 in parts, but labour is significant. The turbochargers are welded directly to the exhaust manifolds and the engine must be removed from the car for turbo replacement. Full turbocharger replacement at a dealer costs €2,500-3,500 per side. Most owners live with the rattle as it is cosmetic, but it can eventually cause boost control issues and limp mode if wear becomes severe.

The M156 suffers from premature camshaft lobe and hydraulic lifter wear, particularly on engines with extended oil change intervals or the wrong oil specification. Early production engines (2007-2009) used softer camshaft material. Symptoms start as a persistent ticking that does not subside after warmup, unlike normal cold-start lifter noise that should disappear within 30-60 seconds. Camshaft adjuster backplate wear is also common, where the locking pin bore wears oval. Replacement of camshafts and lifters on one bank costs approximately €1,500-2,500. Both banks together run €2,500-5,000 at a specialist. Updated INA lifters with improved hydraulic circuits are available. Oil changes every 10,000 km maximum with quality 0W-40 or 5W-40 oil significantly reduces risk. A class action lawsuit was filed in 2011 over this issue.

The MCT (Multi-Clutch Technology) transmission replaces the conventional torque converter with a compact wet clutch for launches. This clutch wears over time, especially with aggressive driving or frequent stop-start traffic. Typical lifespan ranges from 50,000 to 120,000 km depending on driving style. Symptoms include judder on takeoff, harsh 1-2 shifts at low speed, and eventually slipping under hard acceleration. The clutch is integrated into the transmission and requires specialist equipment for replacement. An independent AMG specialist charges approximately €2,500-3,500 for clutch replacement, while a dealer quotes €4,000-5,000. The 722.9 gearbox internals are generally robust, but the conductor plate (TCM) can also fail on higher-mileage examples, adding another €1,200-1,800 to repair costs.

Both the M156 and M157 engines are prone to oil leaks from valve cover gaskets and the crankcase ventilation/oil separator system. On the M157, a particularly insidious failure mode involves oil wicking through camshaft adjuster solenoids into the engine wiring harness, eventually reaching the ECU and causing cascading sensor faults. Dealer quotes for harness and ECU replacement can reach €8,000-12,000, though the problem can be prevented with a €50-100 sacrificial pigtail harness extension. Standard valve cover gasket replacement costs €800-1,500 at a specialist (Mercedes warranty time is 13 hours for the job). Oil separator replacement on the M157 runs €600-1,200. Regular inspection for oil seepage at every service is recommended.

The M157 uses direct fuel injection exclusively, with no port injectors to wash the intake valves. Over time, oil vapors from the crankcase ventilation system deposit carbon on the back of the intake valves, restricting airflow and causing rough idle, reduced power, and slightly increased fuel consumption. The issue becomes noticeable typically between 80,000 and 130,000 km. Walnut blasting (the preferred cleaning method) costs approximately €600-1,200 at a specialist. Mercedes does not officially recommend this service. While not a failure per se, it gradually degrades engine performance and responsiveness, and is worth performing as preventive maintenance on any high-mileage M157.