Brianrehg

I have a 2007 Cayman base model and a few weeks ago it started smoking like a fog machine out of the tailpipe. No other issues with the car so I replaced the AOS. It smoked pretty bad still so I took the intake apart and cleaned all the oil out of it. I have driven it a few times since only for about 15 minutes each time. I now have puffs of random smoke from tail pipe and small amount of white blueish smoke from tailpipe. Not sure if I should keep driving and see if it works iteself out or if I should have it checked. Car runs great otherwise with no issues. it has 120k miles.

Schnell Gelb

Do you have a misfire code?
Does the white smoke only emit when the engine is cold?
If the newer to both the above is "Yes" -be careful -it could be a leaking-open injector overfueling.You may notice the header is wet near the leaker. If you run the engine until the cat gets hot you may get flames from the exhaust and you may destroy the Cat.
So do a fault code check for "Misfire"
Then check for spark ,compression and Vacuum at the oil filler cap(less than 5" water) .If all good ,suspect leaking injector(s).
Disconnect the AOS hose and plug(Pelican hack) .That will eliminate AOS from the suspect list

Brian C in Az

A faulty injector will cause black smoke
White/blue smoke is oil and is leftover residual from the failed AOS most likely.

Since most of the white/blue smoke stopped after cleaning the intake, I would use a can of MAP/ TBI aerosol cleaner. Follow the instructions on the car and that should end the problem.

Schnell Gelb

"A faulty injector will cause black smoke"
NOT when the engine is cold. Yes it may cause black soot(Carbon) on a plug but not from the tailpipe when the engine is COLD.

Macster

Is the oil level ok? Is the oil an approved oil? How many miles on the oil?

Keep in mind the AOS might have been not working very well some time before it failed and this could have the oil more heavily contaminated with water than it would be otherwise. Contaminated oil is more likely to foam and create more vapor and the new AOS might be overwhelmed.

Some smoking after having an AOS fail and replaced is "normal".

When my 2002 Boxster suffered its first AOS failure, and was smoking very bad, so bad in fact the engine suffered a mild hydraulic lock up from the amount of oil/oil vapor the bad AOS was passing through to the engine, the SM at the dealer said it can take some driving to really "flush" the oil out of the engine.

The combustion chambers/cylinders proper of course get flushed of the oil rather promptly -- although in some cases can need some help in the form of the plugs being removed and the engine cranked to remove oil that has collected in the cylinders -- but the intake manifold, the hose from the AOS to the intake and the hose connector can retain some oil. The colder parts of the exhaust manifold can retain some oil, too.

The SM told me it can take maybe 50 miles of driving for the oil to be gone. In some cases the CEL can come on with a misfire or an O2 sensor code. The SOP is to clear the code and road test the car.

I was out of town -- at a job interview 2K miles distant from the dealer/car -- when the first AOS was replaced and the SM drove the car a bit and reported it was not smoking but the CEL came on. It was an O2 sensor error. Long story short I couldn't do much then as I had accepted a job in CA but bring the car with me to CA and after a month or so after I got settled in my new place and new job here I replaced a pair of O2 sensors.

The 2nd AOS failure -- at which time the engine was smoking pretty bad -- after I picked up the car after having the AOS replaced I drove the car around town for a while and when I was comfortable the car was ok I headed out on the highway and drove around 90 miles at highway speeds. I never really remember any smoking and the car/engine was fine both around town and on the highway. A few days later I headed home and drove the car 2K miles back to CA with no issues.

After the 3rd AOS failure -- in this case the severity was somewhere between the 1st one and the 2nd one in terms of smoking and how the engine was running -- when I picked up the car the engine smoked upon start up and even turned on the CEL just as I was leaving the dealer. I forget the error code now but once home I read then I cleared the code.

With the bit of smoking and the CEL I made sure to drive the car quite a bit around town as kind of shake down test and the car and engine was fine. The CEL didn't come back on. After the shake down drive I put the car back into "normal" service and it was fine.

Absent overfilled oil or some other "oil" problem as long as the engine is running ok and the CEL remains dark -- and a check finds no pending errors -- my layman's opinion is just drive the car. A couple of 15 minutes of running is not going to get the engine that hot, is not going to have the air flowing through the engine's intake and out its exhaust with much force/velocity so some residual oil is probably still present. As you use the car this can make itself known by a brief puff of smoke.

But if you want to have a professional Porsche tech check the car over that's up to you. Better safe than sorry.

danschy

Agree with Macster. You can pretty easily tell the difference between oil and fuel burning. Excess gas burning off has a very sharp, acrid odor and is very white. You will see that when you start and stop your Cayman multiple times without driving it, like sometimes happens to me when I have to juggle cars at my place and you burn off the excess fuel due to start up enrichment. Oil is more bluish/gray and not as sharp smelling. My old 88 Dodge Caravan with a Mitsubishi engine would occasionally fill my garage with oil fumes from the worn lifter seals.

altonj

You could have oil in the exhaust from the failed AOS that need to get burned out...

Cheers

Schnell Gelb

Maybe ? - more likely the AOS-realated oil accumulated in the corrugations and depressions of the intake plenums and AOS tubes/hoses.Then it is sucked into the combustion chambers.
To have residual liquid oil in the exhaust system even after running the engine would require massive oil leakage. A cold engine - different story.