2011 Countryman S, auto, 115k, bone stock, it has a whining noise 20 seconds after starting up. I have left it running for 10 minutes and the noise is still there. If I shift to "drive" after the first minute, the noise is gone. It only happens at first startup. It wont do it later in the day, daily driver put 20 miles daily on average. Any suggestions to what it might be? thanks in advance.

 

if you're mechanically inclined, try process of elimination:

pull the water pump tensioner pulley to eliminate the water pump, is the noise still present?
if yes, with pulley still in "service" more, remove the belt and see if the noise is still there.

if you can post a short vid of the noise, that would be better. try to aim low towards the water pump and up to the other pulleys of the AC and alternator.

 

Here's my guess, I could be wrong:
The PCV membrane in the valve cover has a tear and is blowing air as the crankcase heats up. You will either need to replace the whole valve cover (expensive) or get a N18 membrane off E-bay (and a valve cover gasket) and refit your existing valve cover. The danger with that the plastic PCV cover may break when attempting to take it off. Check for air blowing out at the left rear of the valve cover.

https://www.ebay.com/itm/Membrane-va...8AAOSw9GhYhPZW


Edit: Me no read gud. If it's lasting for 10 minutes, it's prob not the PCV. Gonna need more details. How long has it been doing this? Is it getting worse over time? Does it change with engine RPM?