While driving in town quite normally, my 2005 Citroen C4 2L HDI 40k miles, suddenly over-revved, revved up and down a few times, revved incredibly highly and then promptly stopped and wouldn't restart. The RAC guy took me to an RAC recommended garage and the garage eventually reported that the engine was "overfull with oil" (strange as It was due for service and hadn't been topped up for months). On removing the sump they found that the "number four piston had seized and bent its con-rod". They've quoted me £6k for a replacement engine. The car isn't worth any more than £6k. And surely John, the problem of the over-revving is unlikely to be 100% solved simply by replacing the engine? Surely it will have been the over-revving that will have caused the piston to seize? So presumably I will also need to replace something else?