987 3.2 S 'puff' of smoke on start up - Page 2 - Boxster/Cayman - PistonHeads UK

Hi, on starting my Boxster burns a little oil when it has been sitting in the garage for a few days, the smoke clears after a few seconds and all is normal, can any one advise what the cause might be. Ie. worn ?? seals?? before I venture near a garage to sort it out? This is a 2005 car but had a replacement engine in 2009, since then this engine has covered 35k miles. It is concerning me a little, otherwise she runs wells and uses very little oil. I am new to the Porsche brand; previous Caterham x 3 & Lotus x 2 owner. Simon N

I think that they all do that.

I hear they all do that. Something about being a boxer engine.

Move along, nothing to see here....

Perfectly normal. Boxer engines leak a little oil down into the cylinders which burns on ignition... nothing at all to worry about. Some of my porkers have been worse than others. It's just embarrassing sometimes when you've a few people around! G

simonjn said: Hi, on starting my Boxster burns a little oil when it has been sitting in the garage for a few days, the smoke clears after a few seconds and all is normal, can any one advise what the cause might be. Ie. worn ?? seals?? before I venture near a garage to sort it out? This is a 2005 car but had a replacement engine in 2009, since then this engine has covered 35k miles. It is concerning me a little, otherwise she runs wells and uses very little oil. I am new to the Porsche brand; previous Caterham x 3 & Lotus x 2 owner. Simon N I do not subscribe to the belief the oil seeps past the rings. The tendency of oil is to flow away from heat and the piston crown and combustion chamber are hot when the engine is shut off. Put some cooking oil in a flat pan on the stove and turn on the heat and watch as the oil collects in the cooler spots. The hotter spots are almost dry of oil. My theory is the oil comes from the lousy AOS. When the engine is shut off there is some oil on the intake runners across from where the AOS hose connects to the intake. This oil is there because it was not removed from the crankcase fumes that were routed to the intake through the AOS. The engine is shut off and the intake warms up from the heat soak. The oil then runs down into a cylinder if the intake valves are open. If they are closed the oil puddles on top of the valves. When the engine is started some oil smoke is the result. As long as it is short lived, and the engine doesn't exhibit any other signs of distress or noises it is nothing really to worry about. You can help avoid smoking by avoid over filling the engine with oil. Use the right oil. Do not run oil too many miles as the oil gets contaminated with unburned fuel and water (combustion byproducts) and this makes the oil more like to vaporize in the crankcase and overwhelm an easily overwhelmed AOS. No need to get all crazy with the oil change interval. I like 5K miles (and practice all the other things I mentioned above) but even so both of my Porsche engines smoke once in a while -- a great while -- upon cold start.

Rockster said: You can help avoid smoking by avoid over filling the engine with oil. That would seem to make sense. I slightly overfilled my CS deliberatly recently because I was taking it on track and felt it may help a little to combat oil surge. When I restarted it after each run it briefly produced a sizeable cloud of smoke which is something its never done previously in the 4 years I've owned it.

Thank you all for the helpful responses.. not so sure about the 'move along response', anyway I am feeling slight better about the smoke issue. I am surprised that a Porsche Engine would do this, as a past Lotus owner I would have expected my cars to have done something like this! Can anyone define what an AOS is please? I haven't completed the Porsche Acronym training course yet. Where can I buy or download a decent maintenance manual for a 987 from anywhere, I have looked on line but not seen what I want. Haynes level of detail would be fine if they did one. Lastly what to owner think of remapping the engine for an improved throttle response/pick up?

Air/Oil Separator

simonjn said: not so sure about the 'move along response' I think he just meant that there was nothing unusual in what you were describing.

BillTheButcher said: simonjn said: not so sure about the 'move along response' I think he just meant that there was nothing unusual in what you were describing. Yes!

On the book front, try: http://www.amazon.co.uk/Projects-Porsche-Boxster-M... (Will cover the majority of the tasks well that you might do but isnt exhaustive). For the 986s there is a service manual by Bentley that covers basically everything, but I don't know if a 987 version exists. Otherwise Boxa.net has a good community and plenty of advice to help as required.

Many thanks for the link, looks a good buy. I think I may have bigger issues with the car though, despite what has been said on this thread, more smoke tonight when I started her but quite a lot almost smog! Strange as nothing last night. Also very tappety from NS bank which I had not noticed before, oil half full according to guage on the car. A trip to the local service centre in Bedford becons this weekend. Sadly.

simonjn said: Many thanks for the link, looks a good buy. I think I may have bigger issues with the car though, despite what has been said on this thread, more smoke tonight when I started her but quite a lot almost smog! Strange as nothing last night. Also very tappety from NS bank which I had not noticed before, oil half full according to guage on the car. A trip to the local service centre in Bedford becons this weekend. Sadly. Your AOS is the first point to start at, about £100 for the part. Get it replaced, it's the most common thing to cause oil in exhaust at start up. Effectively the rubber diaphragm inside the AOS can split and allow oily vapour to pass up into the inlet manifold pipework. Not usually enough to notice when driving, but will collect in the pipework when left standing and then all come out at once when restarted a while later. After that you're likely looking at some of the other various engine issues, none of which are cheap to rectify. I know, having just had to have my 986S cylinder head replaced due to cracking, £2500 grand down for a second hand head to be fitted!

Car booked in for new AOS on Thursday, saying my prayers it is only this! Simon

My Cayman S does this. It's generally after a short drive (10-15 minutes) and then on the subsequent start up. It throws out a fair amount of smoke — fine if I'm driving off straight away, but in a London side street and having to get out of a parallel parking situation it can be a bit of an embarrassment. Doesn't seem to do it after the car has been properly warmed up. I tend not to drive the car if I'm only going around the corner — so typically it doesn't seem too bad. Not sure if above is good or bad — but I guess I should check the AOS — advice would be welcome! James

jcarruthers said: My Cayman S does this. It's generally after a short drive (10-15 minutes) and then on the subsequent start up. It throws out a fair amount of smoke — fine if I'm driving off straight away, but in a London side street and having to get out of a parallel parking situation it can be a bit of an embarrassment. Doesn't seem to do it after the car has been properly warmed up. I tend not to drive the car if I'm only going around the corner — so typically it doesn't seem too bad. Not sure if above is good or bad — but I guess I should check the AOS — advice would be welcome! James The behavior does not strongly suggest the AOS is umm, knackered. The smoking your observe occurs under circumstances that are known to cause brief smoking at start up. As long as the smoking is limited to just a cold start after a previously short trip, the smoking is brief, and is not accompanied by any other untoward behavior the engine and the AOS is probably fine. The AOS can fail in a couple of ways, or in failing pass through several phases when going from good to bad. Having experienced 2 AOS failures I can tell you the smoking phase appears towards the end not at the beginning of an AOS failure. The engine will smoke upon startup and continue to smoke. The last time I let the engine idle over a minute and the smoke just poured from the exhaust the whole time. An early warning of pending AOS problems -- although these can be caused by other things going wrong -- is a hunting idle, a bit of hesitation off idle, a CEL with error codes that point to a low engine speed fueling problem, and at least once a very high vacuum at the oil filler tube cap, so much so that while I could unscrew the cap I could not remove it against the pressure difference.

jcarruthers said: My Cayman S does this. It's generally after a short drive (10-15 minutes) and then on the subsequent start up. It throws out a fair amount of smoke — fine if I'm driving off straight away, but in a London side street and having to get out of a parallel parking situation it can be a bit of an embarrassment. Doesn't seem to do it after the car has been properly warmed up. I tend not to drive the car if I'm only going around the corner — so typically it doesn't seem too bad. Not sure if above is good or bad — but I guess I should check the AOS — advice would be welcome! James I was on the phone to the Porsche breaker buying my new cylinder head at work , for about an hour. That guy could chat. Anyways, as I was talking to him and looking out over the carpark at work some fella wandered over to his black cayman, got in, started it creating a big cloud of white smoke and then proceeded to drive out of the multistory with a plume of smoke following him all the way. Do some googling about Cayman smoke, I think it's not a rare issue, but IIRC it could be an expensive thing to sort.

Just to round off this thread, I had the AOS changed on my Boxster during the week by a very helpful team at Auto2000 in Bedford, three starts from cold since and no smoke seen since. This car was based in London prior to my purchase and did a higher number of short journeys in the last 2 years of its life in traffic, maybe that was a contribtion to the demise of the AOS? Early days but hopefuly this was the cause of the cloud of smoke on start up. Otherwise the car is running very well. Thanks again to the very helpful contributions to this thread. Simon

Curious, where is the AOS fitted on the engine? A picture could explain a thousand words My car has a quick puff when starting up stone cold, sometimes, I can't figure out a pattern though.

As best I can tell usage doesn't play a role. The 1st AOS on my Boxster lasted nearly 80K miles. My driving didn't involve hardly any short trips. The 2nd one lasted maybe 100K miles again with few short trips and overall warmer (milder at least) temperatures. The AOS in these cars suck. Before they go bad they do not generally do a good job of removing oil vapor from the crankcase fumes. And then they go bad.