911 C4, 2001, 96,000 mi.
There was no event, I just went out after work to drive home, started the car and backed out of my space into some blue smoke.

This morning, I started up and watched the tailpipes. Left side started putting out blue smoke. Right side was white (it's cold here) and then added only a teensy bit of blue, barely detectable.

After about 2 minutes, the smoke cleared. No symptoms while driving.

I presume I'm leaking Oil into the cylinder from somewhere. Does anyone have experience with this one?

I haven't been mistreating. Is this a common issue?

Thanks

 

Blue smoke=burned oil

If it's a puff at start up, most likely, you only ran the car for a very short time the last time it was started, usually the culprit.

If it's more than just a puff, the next most common culprit is the AOS. You can check this by unscrewing your oil cap while the car is running. If it's really hard to get off, there's more vacuum in the crank case than there should be and the AOS needs replacement.

 

Hate to say this but the symptoms sound like it could be cylinder scoring. Monitor your oil levels every 500-1k and see if you're losing any oil.

 

AOS most likely.

The smoke from one side is because the AOS feed tends to favor one cylinder bank over the other especially if the AOS is passing through a lot of oil vapor.

The cap test is a good one but even if you can remove the cap with relative ease that doesn't let the AOS off the hook.

IF it is the AOS you do not want to run the engine any as the AOS can pass enough oil to possibly hydro-lock the engine. Another risk is you shut off the engine and the oil that has been passed by the AOS to the intake then drains down and it can run into a cylinder through open intake valves, or collect on top of the valves if they are closed and when you go to start the engine the oil can then lock the engine. There is not much free room in the cylinder when the piston is all the way up to the top of the cylinder during a compression stroke.

 

What's the remedy for cylinder scoring? Do I want to know? ($)

 

Sounds like I'll be replacing AOS this weekend. And, prob clean the MAS as long as I'm removing it to get to the AOS. Thank you for your response.

 

Let us know how hard it was to replace the AOS. Posters say it is a PITA but I would like to read your comments. Thanks.

 

One more symptom. See Pic! Is this condensation in oil filler tube?

 

Yes just condensation from short trips and not letting the engine warm up enough to burn it off.

This can and does happen on many cars, not just Porsche's.

 

The remedy for cylinder scoring? You started out with the right answer, you just didn't finish it: ($) + $$$$$$$$.

You replace the engine with a new one (if cost effective) or have the existing engine repaired/rebuilt, or you source a replacement engine from a salvage business.

Far more engine smoking episodes are AOS related though and if the smoking was from a scored cylinder I think you'd hear something.

(My 2002 Boxster has gone through 3 AOS's and zero scored cylinders.)

 

Yes.

You need to drive the car for longer periods of time to get it fully up to operating temperature and keep it warm longer or you need to change the oil more often. And maybe doing both ain't a bad idea.

However, what you see can be partially due to an under-performing AOS which is not as effective as removing oil and water vapor from the crankcase fumes.

 

And now, as of today, I can add a Clacking sound. About medium volume level. Sound seems to be coming from both sides of lower rear bumper area.

I hope the AOS clears the smoke symptom for just $120 OEM.
It's the Clacking that scares me now.

 

I literally have zero drivability issues, acceleration, gauges are all perfect, no leaks under the car.

 

One more symptom. See Pic! Is this condensation in oil filler tube?

Yuck! I sugggest you start by getting an oil change, then drive it. When you do drive it you need to drive until the oil comes to pemt, 180* to prevent this.

 

Cylinder scoring can mask itself like a healthy motor initially with the only signs being occasional puffs of smoke and a bit of oil loss. Eventually this gets worse and worse.

I'm not trying to purposely scare you and it may simply be an AOS.

If you really want to know for sure, you can always borescope through the spark plug holes. If you want to be more thorough, you can also drop the sump and peek into it from the other direction too.

Either way, I would recommend doing an oil analysis after you've replaced the AOS and have had a chance to drive it for awhile.

Good luck.