While driving my C220 W204 a warning came up saying "check engine oil when next refuelling". Because the engine started to sound rough I drove the four miles to the main dealer very gently. The engine did not overheat nor was there a warning of low oil pressure. However, the engine required a complete rebuild costing thousands of pounds - this despite the fact that the car had always been seviced at a MB main dealer. The leak was from the timing chain tensioner oil seal which had not been leaking at all before. Has anyone else had such a catastrophic experience?