On a COLD start, the car produces an intermittent buzzing/vibrating noise, like a fan rubbing against its housing shroud. It goes in and out for about a minute, usually as I am backing out of the garage. Then it stops within a minute or two, and does not recur until the next cold start. Ideas?
Not much to go on. Does it vibrate in park or neutral or only in reverse? Can you tell If it in front of vehicle or underneath? Maybe you can get an assistant to listen from the outside of the car with the hood open when noises are predicted.
This could be anything from a loose/damaged heat shield on the exhaust system, to a malfunction of the ABS self-test. Unless the noise is localized for us, we are all just guessing.
HuMy 2006 Outback H6 makes a noise like this for the first few minutes and it’s a loose heat shield on one of the catylitic converters.This can be confirmed by either checking the shield for looseness when the car is cold and engine not running or pressing on it (with a long tool while you stay safely to the side) while the noise is occurring, to see if you can temporarily make it change or stop.
The dealer quoted over $600 to fix mine (over $300 for the part) but many people find a way to prevent the vibration by clamping them. Check the Subaru specific forums for details. It could be other things but this seems to be a common problem with Outbacks.