So ever since it has gotten quite cold here, ive noticed there is a chatter when i start my engine in the morning. I changed oil recently (though i was getting the same noise before) I have been using mobil one, and recently gave castrol syntec a try. Anyhow it sounds like chatter from the valvetrain, and it goes away immediately. Is this bad? Is it becasue there is not yet oil covering the valvetrain? I dont see any way around it short of cranking the engine and not letting it start, or getting a block heater? It's a 2000 SVT.