I have a 2009 EX, 4 cyl. AT, with slightly over 40K miles, purchased new in September 2008. I have had the VTC actuator replaced twice, most recently in January 2011. Two different dealerships have replaced the actuator (I had issues with the first dealership over some brake work). I have mainly used Honda 5W-20 with a Honda filter. This past summer I used Honda 0W-20 and last week used Mobil1 0W-20 when the oil was changed (the nearest dealership is an hour away from me). Until this week, the rattle/grind has been intermittent at best; this week it's happened on the last three mornings when I've first started the car. I realize there is a possibility that I've gotten three bad actuators, though I doubt that's probable. The only constants I've noticed are cold temperatures, usually around or below freezing, and a cold start. Any thoughts or opinions on what this could be other than the VTC actuator? I'm now out of warranty so the idea of having the dealership poke around in the engine could get expensive quickly. The rattle sounds like someone pulling a chain through a pipe. I've followed the posts about the actuator, and this is driving me nuts. Thanks in advance.