Is it cold, if so its condensation my friend
Have a 2010 Mini Cooper S with 55,000 miles and am in Miami, Florida > the weather is definitely not cold > the white smoke only seems to happen when I am idling for any more than normal length of time with the a/c on > I do not have an oil catch can > did the walnut cleaning about 10,000 miles ago > am going to start using 40 wt synthetic oil (which is recommended for hot climates)and add some Seaform > there is evidence of oil on the valve cover and in the valve cover bolt holes > do not notice a pronounced turbo whine > there is no loss of power > have not yet checked plugs > need to determine if I have a failing turbo, a failing valve cover and PCV valve, failing valve stem gaskets > it does not seem to smoke when driving, coming to a stop, or upon startup > I do seem to use a quart of oil every couple of thousand miles > most frustrating and I do not want to start changing parts out > any pointers?Is it cold, if so its condensation my friend
Good news is valve seals are a relatively simple fix. Valve cover off, compress/remove valve springs and keepers, replace seals, reassemble. Takes some special tools and specific knowledge though, you generally can't do the job in the driveway with just a set of sockets.Cold Engine
One of the most noticeable signs of worn or cracked valve stem seals will be just after a cold engine start. If the vehicle has been sitting for any length of time or even overnight, the top of the head inside the valve cover will be coated with residual oil that was pumped up earlier during running operation. The rubber valve seal has also cooled during non-operation, which causes it to contract and leave a small gap. When the engine first starts up, residual oil gets sucked down through the bad seal and into the combustion chamber. A large cloud of blue-white smoke will be seen exiting the tailpipe just after start-up.
Idle and Stop and Go Driving
Bad valve seals will show themselves during prolonged idling at stop signs or stop lights in congested city conditions. When the vehicle sits at idle for prolonged periods, high levels of vacuum at the intake manifold result because the throttle valve remains closed. The high vacuum attracts oil in the heads to congregate around the valve stems. Upon acceleration, the oil gets sucked past the eroding seal and down through the valve guide, where it burns in the exhaust. Huge clouds of blue-white smoke exit the tailpipe after each acceleration from a stop. The burning smoke will disappear during cruising or highway speed.
Evidence of valve seals being compromised will show up during off-throttle braking, especially when descending a steep downgrade where the accelerator pedal remains static. With the creation of high intake manifold vacuum, coupled with the downward slant of the engine, oil collects toward the front of the valve cover over the head. Upon pushing the accelerator after a long coast, burned oil will exit the tailpipe in copious amounts. The engine will continue to burn the oil longer in this case, but it will still be a temporary condition until finally the smoking stops under normal cruise.