Question about brief puff of smoke

I have a question for the forum regarding a occasional problem I am having with my Boxster . I think that I have tested enough to re-create it, so here is my question. I have a 2009 Boxster (2.7), runs and drives great. I have noticed that when I start it briefly like to just move it out for a car wash or to get another car out of the garage and only run it for a few seconds and then park it, I will get a puff of blue smoke the next time I start it a couple days later. It goes away in about 5 seconds, and does not smoke at all when I drive it. If I have it out, get it hot and have driven in for a while and then park it, I never get the blue smoke. This is not an AOS issue (I have had that checked, and the 2009 did not have the same design that caused problems). I am wondering if my theory since the cylinders are flat, could oil be sitting in the cylinders since it did not get hot that just burns off when I start it? Does this make sense to anyone. Is this something that I should worry about. The car has about 48k miles on it. Thanks for taking the time to help.

I think a lot of people will chime in here on this -- I believe this is normal. 987s that either sit or are briefly used and stopped -- you'll get a little oil burn off at the beginning (plus sometimes a bit of a lifter sound, until it warms up). IMHO, this is normal and I wouldn't worry about it. I'll let other chime in but I think you're just fine. Cheers.

Thank you for taking the time to reply and support my theory.

To refine it a little bit, my car (27k orig miles, 3.4l) will puff a bit of smoke on startup if the last run time was not long enough to get up to temperature. It does not do it if I drive it up to temperature and then let it sit for a few weeks or a month. In general, there will be more blowby and more slop in general if it's not up to temp, which will cause it to ingest more oil (still shouldn't be much) at startup. Point is, if it can't get to operating temperature before startup, there will be more unburned oil in the combustion chambers, which will accumulate and burn next startup. Fix, only turn it on if you can drive it for 5 min and get it up to temperature before shutdown.

This exact same thing happens to me (2007 CS), and in the same manner. Move the car from the garage to the driveway, wash it, brief puff of smoke the next time it's started. As you surmise, it is a result of the horizontal cylinders. Nothing to worry about.

PS: your engine is a 2.9L. They shrank it for the 981 series to a 2.7L. And I looked - no intro message? You can create one at: New Member Introductions Pictures are always welcome (and usually demanded.. )

Your motor has port injection like the M-97 powered car from earlier versions. This means that the oil smoke could signal fuel injectors leaking gas after shut down or oil from the valve seals leaking. I've got 70k miles on my M-97 3.4 and no startup smoke, but do run Mutol V 300 Competition 5W-40 and change it every 4000 miles. I have no complaints from this motor oil, no smoke or film in my tail pipes and no timing chain noise. The other idea is to use a fuel additive to help burn any carbon deposits. I use Jectron injector cleaner about every 5 tank full of gas,

[Image-only or quote-only post; no author-written text.]

I’d say it’s time to change your Air Oil Separator (AOS).

I'm not so certain that's the cause. A brief start of the engine from cold, then stopping it leaves a very rich mixture in the cylinders. On the next start - there will be smoke produced from the rich mixture. It's also not good for the cylinder walls since the rich mixture combines with the oil on the cylinder walls - leaving them vulnerable. It's why I always try to give the car at least 5-10 minutes of run time to settle back into the normal mixture before shutting it off, even when just backing it out of the garage. I learned that lesson with a Volvo 950 wagon that would immediately foul the plugs and refuse to start if this happened. It was much less tolerant than the Porsche when mistreated. I'd suggest trying that before going after the AOS. The AOS was a weak point in the pre-2009 engines. It appears that Porsche addressed the weak points in the new IMS-less engine. I did replace mine at a 60,000-mile service, but only because the former owner had purchased one and gave it to me with the car when I bought it. At that time - the original AOS was functioning just fine. I haven't seen many (any?) reported verified AOS failures on the 2009+ engines. And that's what we're talking about here. My reply to that is - don't do that.

"60,000 mile replacement isn't at all unreasonable" when do you replace the AOS on the 981 please and thank you dlb

That's a rather selective quote of what I said.. that statement was in reference to the pre-2009 Boxster/Cayman 987 series engines (and possibly/probably all 986 engines.) Quote from me in an earlier (2 posts up) posting: I noted that I haven't really heard of failures of the later AOSs on 987.2 (2009+) 987s. As far as a 981 - dunno. I can't recall ever hearing of one failing, although I'm sure a few must-have by now. If you know of any that failed let us know - the more data we can gather the better advice we might be able to give.