I have similar vibration, and increased over time from just when cold. My honest mechanic says do not bother to replace until gets worse as it is not all that cheap. As to the fan clutch, mine got to a point where it threw the code for being engaged when not commanded by the PCM. And was almost always engaged. Replaced with Hayden, but still does engage when start moving after stopped, even in cold weather, so I suspect some sensors are off. However all else is fine and just living with it as have nothing to troubleshoot.