2004 Honda Accord Engine Noise when cold

2004 Honda Accord with 120k miles sounds like an old sewing machine when cold for a few minutes (less than 5). The exact sound is on a video on youtube: http://www.youtube.com/watch?v=Sc5LW2eizpY. Dealer said they can’t find it. Car has been maintained well and all services have been done. Any ideas? I’ve heard a lot of guesses (all expensive) but no solutions. Dealer finally got tired of me asking about it and said to just ignore it (turn up the volume on the radio).

I read the comments and listened to the video and it sounds like valves. I would have the valves adjusted and switch to 0w-30 synthetic oil. Ow means it flows faster when cold. 30 is normal operating temp weight.