BMW N53 occasional puff of smoke on startup

[bmwmike]

As subject really, engine has 42k miles and every now and again I see a puff of smoke on initial startup. Clears quickly and no misfiring. Engine hasn't needed a drop of oil in the 6k miles I've owned it.

Just has a full set of injectors replaced under warranty by BMW and was doing the puff before replacement and still doing it after.

Is a sort of grey black cloud. Dieselesque if you know what I mean.

Wondering if it's normal for a GDI engine? Plugs looked OK too, not oily. One had oil on the thread but I can't work out where that came from.

Not sure it's worth getting BMW to check it out at £90 per hour. Runs fine etc.

Thanks
Mike

[bmwmike]

Thanks.

No blue, more black like a diesel. The injectors were my first suspicion but as I say they've been replaced.

Almost like it's very rich immediately on startup then clears.

Plugs looked OK but a little sooty. Exhaust was getting very black before new injectors but is staying clean much longer since new ones.

Didn't see any oil in the spark plug well, was spotlessly clean. I wonder if there is a problem on that cylinder as you suggest. Put a new plug in will check it again in a few miles.

[bmwmike]

Hmm did it a tiny bit today and may have a blue tinge after all. Will try and get a better video.

Is the n53 known for valve stem seals failing ?

[bmwmike]

227bhp said:

It's known for far worse than that: http://www.pistonheads.com/ugassing/topic.asp?h=0&...

I think that applies to engines which actually consume oil though. I haven't topped mine up yet, had it 6000 miles.

[bmwmike]

I managed to get a video of it. Doesn't happen all the time.

https://www.dropbox.com/s/21vzxy7wts49htd/20160904...

Anything to be concerned about ?

Thanks

[bmwmike]

Thanks. So is it in the bounds of normal or a fault? I have a warranty with BMQ (mondial).

[bmwmike]

Just thought I'd follow up on this thread. Car is now on 46k miles. Wow I really don't do many miles.

Still get the occasionally puff of blue smoke on startup but never noticed it on over run (and I've tried... 6kprm in 2nd etc). Occasional white smoke at lights.

If it was valve stem seals wouldn't it be much worse by now?

Thanks

[bmwmike]

E-bmw said:

That will be steam, obviously it will be more noticeable close after start up & especially on a cold day.

I thought so too but on my internet travels I saw several references to white smoke caused by valve stem seal failure. Apparently if oil is very hot it burns white not blue. New one on me.

I booted it full throttle from idle in second earlier and in my rear view mirror a cloud of blue smoke. First time I've seen that. Not sure if it was my car though was my lane but can't recreate it.

Think i should sell and get a s62 m5. Mmm.

[bmwmike]

bmwmike said:

...
I booted it full throttle from idle in second earlier and in my rear view mirror a cloud of blue smoke. First time I've seen that. Not sure if it was my car though was my lane but can't recreate it.
...

After extensive testing attempting to recreate the plume of smoke I have concluded that it was tyre smoke

So the occasional puff of blue on start up but mostly a completely clean exhaust.. one for my blind eye to look at from now on!