The OM651 is Mercedes' 2.2 litre four-cylinder diesel, fitted to C-Class, E-Class, Sprinter and others from 2008 onwards. Owner and workshop reports cite swirl flap failure causing engine damage as the most serious concern.
This Engine Guide guide combines structured analysis β verdicts, risk scoring and cost ranges where we have enough data β with real fault cases pulled directly from MyCarFault's reporting database, so the guidance below reflects what owners actually experience rather than manufacturer specifications alone. Background and analysis come first, followed by the linked fault reports and related guides you can jump to directly using the links above.
Based on owner reports and community discussions, typical costs range from Β£400 to Β£4,000. Costs vary significantly by vehicle age, region and whether OEM or aftermarket parts are used.