Just a quick question that someone who knows more than me can hopefully answer. My '04 Nissan Altima 2.5 has the noisiest valve train that I have ever heard especially in the cold weather. Is this due to it being VVT? I don't think it is a problem with my engine as a guy I work with complains of the same noise with his '04 Altima and I read on this forum of other members having the same complaint. Thanks for any answers.