Popular executive diesel known for comfort and economy. Much more reliable than the W211 predecessor. The OM651 engine is proven and capable of very high mileage when properly maintained - commonly used as taxis. Key concerns: early models (pre-2011) had piezo injector failures (later fixed with magnetic injectors), timing chain tensioner wear typically after 150,000 km, rear subframe corrosion in salt-heavy climates, and electronic steering lock failures after 8-10 years. The 722.9 7-speed automatic is generally reliable. Facelift models (2013-2016) are recommended - more efficient, better transmission calibration, and Euro 6 compliant.
Typically occurs between 100,000-150,000 km. Early warning sign is a rattling noise for a few seconds on cold start. The tensioner has an oil release valve that weakens over time, allowing pressure to bleed overnight. Mercedes technical guidance states chains should be replaced before 250,000 km or they may break. Parts cost €550-600 for OEM timing chain kit; specialist labor €700-1,500. Some dealers quote €4,000-7,000 by removing the engine, but skilled independents can do it in-place for much less. If ignored, chain can jump teeth causing catastrophic valve/piston contact.
Early piezo injectors fail, later magnetic versions reliable · more· less
Pre-2011 models with Delphi piezo injectors had widespread failures - approximately 300,000 OM651 engines affected worldwide. Mercedes issued a service measure to replace them with magnetic injectors free of charge. Symptoms include rough idle, reduced fuel efficiency, black smoke, difficulty starting. Some failures occurred as early as 5,000-10,000 km. Post-2011 models with magnetic injectors are much more reliable. Typical replacement cost €300-600 per injector; full set €1,500-3,000. If buying pre-2011, verify injectors have been updated.
Motor brushes wear out after 8-10 years, preventing engine start · more· less
Common failure affecting W204, W207, and W212 models. The ESL motor typically lasts around 130,000 km or 13 years before carbon brushes wear out. Early symptoms: need to insert key multiple times for steering to unlock, clicking noise from steering column. When failed completely, steering won't unlock and engine won't start. Dealer repair €700-1,200 (3-4 hours labor plus €700 part). Independent specialists €300-650. Some repair services offer motor replacement for €180-450. This is a theft-related part only available from Mercedes. Newer Mercedes models don't use ESL due to reliability issues.
Rear subframe corrosion€1,500 - €3,500
Corrodes from inside out in salt-heavy climates, hard to detect · more· less
Known problem on W204 and W212 models driven in winter climates with road salt. Water and salt collect inside the subframe and corrode it from the inside out, making damage difficult to detect during routine inspection. Mercedes extended warranty to 20 years/unlimited miles for subframe corrosion with perforation. If subframe fails, can cause fishtailing while braking, sudden veering, or complete loss of control. Mercedes replaces subframes for free in many countries (except USA according to some reports). Prevention: avoid permanent rubberized undercoating (traps water); spray Waxoyl or POR-15 inside subframe regularly. Replacement cost €1,500-3,500 if not covered by warranty.
Clogs with short trips, needs high temperatures to regenerate · more· less
Very common issue, especially with urban short-trip driving. DPF needs high temperatures (sustained highway driving) to regenerate and burn off soot. Symptoms: warning light, decreased engine power, poor fuel efficiency. Forced regeneration at dealer €100-800. DPF cleaning service €300-800. Full replacement €1,200-4,000 but rarely needed - typically only after 200,000+ km. Most issues resolved by forced regeneration. Prevention: regular longer drives on highway; avoid only short trips; address warning light immediately before it turns red (more expensive repair).
EGR valve and intake manifold carbon buildup€400 - €1,500
OM651 diesel engines suffer from intake manifold swirl flap issues due to soot buildup, especially under urban driving patterns. Occurs typically between 80,000-120,000 km. Symptoms: hesitation, rough idle, performance derate. EGR cleaning €200-500; replacement €800-1,500. Intake manifold cleaning when combined with other work €200-500; standalone €400-800. Complete manifold replacement €1,200-3,000. Prevention includes quality diesel fuel and long enough drives for proper DPF regeneration. Periodic intake/EGR cleaning recommended.
Water pump failure€500 - €1,200
Electric pump fails around 100,000-180,000 km, plastic construction · more· less
OM651 water pumps are known weak points - plastic construction as cost-cutting measure. Fails typically between 100,000-180,000 km. Symptoms: coolant warning light, engine overheating, poor cabin heating, coolant loss, weeping from seals. Some owners report metal aftermarket versions available that don't have the same failure rate. Parts cost €400-500 (electric pump integrated with thermostat housing). Labor typically 4-6 hours. Total €500-1,200. Recommend OEM parts from Mercedes rather than aftermarket. Replace thermostat at same time to prevent future issues.
Transmission valve body / conductor plate€1,000 - €2,800
722.9 transmission issues typically after 100,000-150,000 km · more· less
The 722.9 7-speed automatic is generally very reliable - most early problems were resolved by 2010. However, when serious mileage of 100,000-150,000 km is reached, valve body issues can occur causing shocks, bumps, slips when shifting. The conductor plate attached to the TCU is a common failure point. Symptoms: difficulty downshifting, error messages, gearbox limp mode, complete blockage. Dealer replacement €2,300-2,800. Independent shops €1,000-2,000. Regular transmission fluid changes every 60,000-70,000 km significantly improve reliability (Mercedes specifies 37,500 km officially).
AIRMATIC air suspension (if equipped)€2,000 - €5,000
Air springs leak after 10 years/100,000 km, compressor fails · more· less
Only affects models with optional AIRMATIC suspension (standard suspension with coil springs is much more reliable). Expect to replace rear air springs and front struts around 10 years/100,000 km as rubber bladders develop leaks. Single air spring replacement €1,200-2,500 per corner. Compressor replacement €1,100-1,200. Addressing multiple leaks and failing compressor can quickly reach €3,000-5,000. Moisture in compressor causes corrosion and early failure, and can push moisture into air springs causing more damage. Non-AIRMATIC models have simpler issues with rear suspension level sensors. Recommendation: avoid AIRMATIC if possible.
Turbocharger wear€800 - €2,000
Bearing wear or seal failure typically after 120,000-200,000 km · more· less
OM651 turbo issues are relatively rare with proper maintenance. Symptoms: oil mist/smoke, whistle, low boost, lag. Typical occurrence 120,000-200,000 km. Causes include bearing wear, seal failure, oil starvation. Turbo overhaul €600-1,200; replacement €1,200-2,000. Prevention: regular oil changes with proper MB 229.51/229.52 low-SAPS oil every 10,000-15,000 km; allow post-load cool-down (let engine idle 30 seconds before shutting off after hard driving).
Solid and reliable with proper maintenance
The W212 E220d is significantly more reliable than its W211 predecessor and capable of very high mileage - many examples exceed 300,000 km with proper care. The OM651 engine is proven and widely used in taxis. Main concerns are early model injector issues (already fixed by Mercedes), timing chain maintenance after 150,000 km, and electronic steering lock around 10 years. Regular servicing every 15,000 km and transmission fluid changes are essential. Facelift models (2013-2016) are recommended.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete Mercedes dealer or authorized specialist records essential. Verify servicing every 15,000-18,000 km with correct oil.
Tires
Check tread depth, age (date codes), uneven wear patterns. Run-flat tires are very expensive to replace.
Cold start
Must start engine completely cold. Listen for timing chain rattle in first 30 seconds.
Body condition
Check for rust, accident damage, paint mismatch. Inspect underbody thoroughly.
Test drive
Minimum 20 minutes including highway speeds to get DPF and transmission up to temperature.
Specific for this vehicle
Cold start timing chain rattle
This is the single most important check. Engine must be completely cold. Listen for rattle/clack noise in first 5-30 seconds. Any rattle lasting more than a few seconds indicates worn chain/tensioner.
Check rear subframe for corrosion
Thoroughly inspect underbody, especially rear subframe attachment points. Look for rust perforation, bubbling. Use flashlight and mirror. Critical check if car has spent winters in salt-heavy areas.
Verify injector replacement (pre-2011 models)
If car is pre-2011, check service records to confirm piezo injectors were replaced with magnetic versions under Mercedes service measure. Test for rough idle, black smoke.
Electronic steering lock (ESL) operation
Insert key and check if steering unlocks immediately. Listen for clicking noise from steering column. On cars 8+ years old, this is likely to fail soon if original.
DPF regeneration capability
Drive for 20+ minutes on highway. Check for DPF warning light. Ask seller about DPF regeneration frequency. Cars used only for short trips will have clogged DPF.
Transmission fluid change history
Verify transmission fluid has been changed at least every 60,000-70,000 km. Test for smooth shifting when cold and hot. Any jerking, delayed shifts, or clunking indicates valve body issues.
AIRMATIC suspension (if equipped)
Check for sagging to one side, uneven ride height. Listen for compressor running excessively. Inspect air struts for oil leaking/misting. This is expensive to repair.
Check coolant level and condition
Low coolant or brown/milky appearance indicates water pump or head gasket issues. Look for weeping around water pump.
Facelift vs pre-facelift identification
Facelift (2013-2016) has single-piece headlights and is Euro 6 compliant. Pre-facelift has quad headlights. Facelift is recommended for better reliability and emissions compliance.
Power steering fluid leak (fire risk)Check with VIN
Fuel filter leakCheck with VIN
Oil leak around chain tensioner (fire risk)Check with VIN
Rear subframe corrosion extended warranty20 years/unlimited miles
Contact Mercedes-Benz with the VIN to verify all recalls and service measures completed. The piezo injector service measure (pre-2011 models) and rear subframe extended warranty are particularly important.
Warranty Status
Factory warranty (2 years)Expired on all W212s
Rear subframe corrosion warranty20 years/unlimited miles (perforation)
Extended warranty availableCheck with Mercedes dealer
All W212s are outside their original factory warranty. However, Mercedes extended the rear subframe warranty to 20 years/unlimited miles for corrosion with perforation (holes). Extended warranty may be available through Mercedes dealers - coverage and cost vary by age and mileage.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.