Hi - I too have had the same problem with our 54reg Grand Senic (Nothing Grand about it) @ 51,000 miles the crack shaft gave up the ghost and wrecked the engine. Sounded like a bunch of clogg dancers jigging on a tin roof. This car was serviced regularly but not through a Renualt dealer and within 1000 miles of the recommended interval. Renault are not interested. Bottom line. It's harsh I know, you have 2 options, get a reconditioned engine for around 3k fitted on take it to a scrappies. I like you have had no end of issues with this car and will NEVER buy another renualt. I know this doesn't help you - but your not alone. Cheers Degzie