Mercedes-Benz S-Class W222 — Reliability

W222 2013–2017 1 engine

Reliability Summary

Engine M278 — 59/100 CAUTION
Known Issues 6

Engine in this model

CAUTION 59

M278

M278 4.7 V8 Biturbo

Mercedes 4.7 V8 biturbo of the 500/550 models (S, SL, CLS, E, ML/GLE, GL), 367-455 hp. Strong and sm...

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Known Issues Across All Engines

Issue Engine Severity Onset
Bore scoring and piston scuffing - oil consumption, engine failure M278 critical —
Timing chain tensioners and check valves (early engines) - cold-start rattle, chain wear M278 high —
Exhaust valve guide and seat wear - misfire, cylinder head repair (warranty extension) M278 high —
Oil wicking from cam adjusters and sensors into the wiring harness and ECU M278 high —
Turbocharger leaks or failure, brittle turbo coolant lines M278 moderate —
Catalytic converter sulphur contamination (warranty extension) M278 moderate —