Got a bit of a problem, here's what happened, I have a 2005 C55 with around 45000miles warranty expired in Feb 08, I was driving home and about 2 minutes before I reached my house I felt a slight misfire which has never happened before, I driving at around 30mph and noticed smoke from the exhaust about 50 metres/10 second after that the engine cut out with a rumbling sound. The temp gauge was reading normal and did not seem to overheat. I checked the oil on the on board monitor and it gave the message "OIL OVERFILL". I opened the oil filler cap and I there seemed to be alot of oil there didnt look like the oil and water had mixed however I cant be sure as I have never seen what this would look like. The car went straight on a recovery to the workshop they say the engine is seized and that they need to take off the head and take a look. Not sure if this is related however the gearchange has been getting very jerky recently and I suspect that the valve body for the gearbox was at fault for the jerky gearbox as a freind of mine with a C55 had a problem with his. Does anyone think that this could have something to do with the breakdown or does this sound like a head gasket, whatever the case I dont think that something like this should happen on a 45000 mile car, anyone have any ideas on what this could be or where I can get a replacement engine?