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Mercedes OM642
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Mercedes OM642
Verdict
RISKY · 48/100
Est. cost /3yr
€2,500-5,500 over 3 years depending on deferred maintenance and whether EGR/swirl flap work has already been done
Oil interval
10,000 km
Recalls
0
Worst issue
Timing Chain Wear and Tensioner Failure
CRITICAL
Mercedes OM642
W211 · W211
Timing Chain Wear and Tensioner Failure
€1,500-3,500
CRITICAL
EGR Valve and EGR Cooler Failure
€400-1,200
HIGH
Swirl Flap Motor and Intake Manifold Failure
€300-900
HIGH
Turbocharger and Actuator Wear
€800-2,500
HIGH
Intercooler Pipe and Boost Hose Oil Leaks
€100-400
MODERATE
Mercedes OM642
W211 · W211
•Pull a full OBD scan for EGR, swirl flap, and turbo actuator fault codes before purchase
•Check timing chain tensioner notch count and ask for documented evidence of chain replacement if over 150,000 km
•Verify full service history with oil changes at no more than 10,000 km intervals using approved MB specification oil
•Inspect all intercooler pipes and charge hose O-rings for oil residue or cracking
•Test drive at full operating temperature and confirm no limp mode activation under hard acceleration
•Check for coolant loss or sweet smell from exhaust that could indicate EGR cooler leakage
•Confirm whether swirl flap delete or EGR delete has already been performed, and if so, ask for documentation of the work
Mercedes OM642
W211 · W211
Timing chain and tensioner
Inspect tensioner notch count immediately; replace chain kit if any wear is evident or history is unknown
120,000 km
Swirl flap actuator motor
Perform swirl flap delete or replace actuator motor preventatively
100,000 km
EGR valve and EGR cooler
Clean or replace EGR valve; inspect cooler for leaks; consider EGR blanking plate if issues recur
100,000 km
Turbocharger actuator
Test actuator operation and inspect for play; replace if sluggish or inaccurate response noted
150,000 km
Mercedes OM642
W211 · W211
No recalls on record
Mercedes OM642
W211 · W211
✓Strong torque output up to 620 Nm makes it effortlessly quick for a diesel
✓Aluminium block and head construction keeps weight down compared to earlier iron-block diesels
✓Well-supported by independent Mercedes specialists with extensive DIY documentation
✓Timing chain longevity is good when oil changes are performed on schedule with correct spec oil
✓Wide availability of parts across the Mercedes platform range due to shared engine across many models
Mercedes OM642
W211 · W211
Real consumption
8.3 L/100km
Official consumption
Not available
Oil interval
10,000 km
Oil spec
MB 229.51 or 229.52 0W-30 or 5W-30 fully synthetic
Est. cost /3yr
€2,500-5,500 over 3 years depending on deferred maintenance and whether EGR/swirl flap work has already been done
Mercedes OM642
W211 · W211
224 hp · 510 Nm
2005-2009
265 hp · 620 Nm
2005-2009
The 224 hp and 265 hp OM642 tunes share the same mechanical base, timing chain, EGR system, and swirl flap design, so there is no inherent reliability advantage to either output level. Choose based on trim and performance preference rather than reliability, and focus buying decisions on service history and documented chain/EGR/swirl flap work instead of the horsepower badge.