I have a 2017 Countryman with 16,000 miles. Recently I've noticed a burst of blue smoke during cold start that fades quickly and doesn't return while the engine is running. My initial guess was leaking valve guide seals that were allowing oil into the cylinders while sitting. Took it into the dealer and was told that wasn't the problem. After much discussion with MINI, the dealer changed the crankcase ventilation tube, but that didn't fix the problem. The plugs are not fouled, but the cylinders appear wet (is what the dealer mech says). The dealer keeps saying they are working with the "Mini engineers" to identify the problem - sounds to me like they really don't have much expertise in house, which confirms the opinion I've always held about dealer repair shops.

Any idea what might be causing oil in the cylinders? It doesn't seem to be an issue while driving (no smoke while the engine is running or idling).

 

Valve stem seals, or valve guides.

Oil drips down the valves,
puddles in the combustion chamber overnight, you start the car, that oil burns off, and clear the rest of the day.

 

That was my guess, but I've been told that wasn't it. Not sure how they confirmed. Today they replaced the valve cover. We'll see what happens.