My 2013 Prius C2 with a total of 4512 miles made an engine noise on start-up. The noise lasted for about 3 seconds after a cold start at 59F ambient temperature. It was a soft clanging sound at about 4 or 5 Hz and there was no engine vibration - the start was smooth. I had moved the car from the driveway to the garage the day before and shut down the engine after it had been running for about 15 or 20 seconds following a cold start. The noise occurred on the first start the next day. I also own a 2011 G3 and I am well aware that the liftback should not be shut down until the warmup cycle is completed. Since I had heard of no similar problems with the C, I shut the engine down without allowing it to complete the warmup cycle the day before. From now on, I will operate my C as I do the G3 - no engine shut-down until the warmup cycle is completed. Read more: http://priuschat.com/threads/potential-solution-to-the-rough-start-engine-rattle.90441/#ixzz300YrTGSs Follow us: @PriusChat on Twitter | PriusChat on Facebook
