I would venture to guess that ...

While driving my 2003 daily driver base model with 80k miles at a slowish highway speed, I noticed white smoke in my rearview mirror. Sure enough, it was me. I pulled over and there was smoke billowing out of my tail pipe (later when much less smoke, it seemed to be only from the driver's side portion of the exhaust system). I waited a while and it seemed to stop. In a possible moment of stupidity, I started it up to get to a safer "pull over" spot about 50 yards down the busy road. Apart from now much more billowing, the car drove fine for that 50 yards. Once safely to the side, I called a tow truck and had it towed to my house where I could try and sort out what to do. The smoke continued to waft out of the tail pipe for the 20 minutes or so that I waited for a tow. It decreased gradually, but for a while there, I worried that I could be on the verge of an engine compartment fire. Didn't happen though. It's now resting in my driveway. Oil level is fine, no puddles on the ground. Coolant level and temperature normal. Dipstick for oil looks fine with no odd color or texture. Didn't notice any odd noises or behavior other than the very large amount of smoke. Electrical system works fine, no warning lights at all. I'm going to open the engine compartment and poke around (check the air filter & other simple things). Will tow it to a repair place bright and early tomorrow. Anyone have suggestions for other things to check before handing it over to a shop? I don't have a code reader, but there was no CEL. I'm rather petrified...

Forgot to add, when the smoke was intense, it may not have been only coming from the tailpipe. I opened the rear trunk and could see it coming into the trunk from the little corner area by the passenger side tail light. More soon after I open the engine compartment.



Edited 2 time(s). Last edit at 03/31/2011 08:14PM by Steve (Berlin & LA). (view changes)

After cool down, anything on the floor? Expansion tank normal height? Smell...oil or anti-freeze?

Could have been either oil or coolant and I don't think I would have known the difference. Definitely seemed white, but again, I'm not the expert on smoke properties. In any case, certainly not black smoke.

... it was the AOS that bit the dust.
Once it passes a bit of oil it can go to the cats and will smoke for a looooong time since the cats get very hot.
If it was that intense, don't start the engine again, as it could hydrolock.
The tech will probably have to clean all of the intake parts as they may be very coated with oil.
Good luck.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

There was nothing interesting to see in the engine compartment. I slid out the air filter as well, with nothing to see. I shook the car when looking at the water level to make sure that I could see it slosh (double checked with a flashlight, and all is well). Thanks guys for the fast replies. This board has saved my butt more times than I can remember! I'm off to dig up old AOS failure threads to see what I can learn.

in these tanks over time for the real coolant level and a real check (removing the cap with the engine cold!) and shining a bright light in the tank opening will find it nearly empty of coolant.

Sincerely,

MarcW.

Signs are just too classic - huge billowing white smoke clouds. Relatively easy DIY to replace the AOS and J tube. Clean out the throttle body,etc.

See my other pastime at www.gothamcityracing.net

Is the oil level down? If so, I'd take Pedro's bet as the AOS. Just replaced one on my 03 about a month ago. Not a hard job but a pain to get to. The 03 is a bit different from most of the DIY instructions in that it fits into the crankcase differently. Still got it done with the older instructions. Smoke gone. Even after 3 days at VIR.

Dave - 06 987 S coupe SG/NL; gone (but still my first love): 03 986 AS/GG/BK;

I cleaned the throttle body myself a couple years ago, so I'm comfortable doing that.

If it is oily -- as I have mentioned before when my car's AOS was going (gone?) bad I pulled the TB and found the butterfly valve (and the TB body's inner diameter) dirty/oily and the buttervalve wet enough with oil that a dirty old drop of it was hanging on the bottom edge of the valve -- this is just a more check mark against the AOS.

Check the area right behind the TB where a hose from the AOS connects. I found this area quite wet with oil. Carefully and with no rings, watches, etc, on your hands or arms to come loose and fall into the engine reach into the intake and wipe the intake walls down with a clean lint free towel that won't shred or come apart. See if you get any oil.

Take pics and report back what you find.

Sincerely,

MarcW.

The picture on Mike's pages (which somehow I always forget to look at before posting here) looks very much what I saw today

[sites.google.com]

feeling a lot less terrified compared to a few hours earlier. may be that bottle of wine I opened though...

You now have all of the classic signs of AOS failure.

Not a difficult DIY, but the lower clamp on the bellows can be tricky if you use an OEM-style clamp. A pair of cable-operated hose clamp pliers makes it much easier to precisely locate the clamp onto the lower bellows.

Regards, Maurice.

Thanks. I've been shopping around for those plier tools. I feel much relieved! I'm filling up online shopping carts and hoping to get things overnighted to me in time for my next workday (not until monday, as luck would have it) since this is my daily driver.

Sorry for the troubles Steve. btw, the smoke in the first photo was burn off AFTER the AOS was fixed. Before it was fixed, I put down a smoke screen across the entire street!

Maybe I'll make a video of my burn off tomorrow. Then again, if something goes unexpectedly, I'd end up with a video full of language not suitable for public viewing.

Here are the instructions for cleaning the throttle body:
[www.pedrosgarage.com]

and here are the instructions for replacing the A/O Separator:
[www.pedrosgarage.com]

The only way oil gets into the combustion chambers is either bypassing the piston rings or coming in from the A/O Separator into the intake downstream of the throttle body, through the open intake valves and into the cylinder(s).
When you remove the throttle body you should see a small pool of remnant oil in the Tee and or crossover tube, depending on your model year.
There will also be oil down into the intake plenums which you should try to remove with a paper towel by sticking your hand into them with a clean towel.
After you reassemble everything and restart the motor you will probably still get another huge smoke bomb because oil is still dripping into the chamber(s) through the intake valves that are half open. It can smoke for a few minutes and then slowly disappear.

The cable-extended spring-clamp tool can be found at Sears and many auto parts stores.
You can replace the AOS completely from the top of the engine using this tool.

Good luck.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

This morning I detached the hose between the AOS and the air intake (not a J-tube on my car, but an accordion like thing with I think the same function). Dipped my pinky into the tube, and in return I got a very well oiled finger. Thanks SO much for those DIY pages Pedro -- an amazing service to the community! I've order the AOS and for some extra cash, it should be at my door Saturday. Also ordered the hose clamp pliers and a long 5mm hex socket for in-store pickup sears. Will pick them up from later today after I get a rental car to do these and other errands. All told, I'll be out about $300. That's about 30 times less than the visions I had in my head when pulling over yesterday. This isn't exactly what I had in mind for my 4-day weekend, but I can think of much worse jams to be in than a required day or two of playing with my car in the driveway.

Oh and reading the various DIY pages, I'm happy that I'm not doing this on the older model car where you have to come at the AOS from below or from the side. Both jobs look awkward, but I think I got the better one in this case.

Great write up, Pedro. I'm about to replace mine and was looking for good instructions.

I'm thrilled! After removing and replacing the AOS, smoking out my neighbors during ~5-10 minute burn off, I took the car for a 15 mile spin. Apart from the initial smoke, nothing unusual going on after repair. By the time my 15 miles were done, the car was completely back to normal with no trace of smoke. Soooooooooooooooo relieved, as this is my daily driver (meaning my only car) and I live about 12 miles from the office.

Saturday delivery from pelican saved my butt. I'm about 4 hours by car from any major city. There's one dealer 2 hours away in Santa Barbara, but they aren't well stocked for parts.
[www.calpoly.edu]

My driveway, and goofy toolbox stickers
[www.calpoly.edu]
[www.calpoly.edu]

The lay of the land in the engine compartment
[www.calpoly.edu]

Yep, there's oil in the intake allright!
[www.calpoly.edu]
[www.calpoly.edu]

A peek down the intake tube upstream of the AOS shows what "clean" looks like
[www.calpoly.edu]

Laying out the various parts after going through a ton of those blue shop paper towels. You can see the top-tube on the AOS that I busted by mistake when removing it. Luckily, I had bought a new one just in case.
[www.calpoly.edu]

A look down the plenums
[www.calpoly.edu]

QUESTION: Is this normal? There was a big sticky glob of grease pooling up on the engine from what looked like an overflow tube. Any help welcome! Would like to fix it if it's a problem in the waiting.
[www.calpoly.edu]
[www.calpoly.edu]

The "middle tube" was a bear to get loose. I abandoned my attempts to remove it. It ended up "popping off" when I dislodged the AOS.
[www.calpoly.edu]

Clamp tool was totally awesome (though even with it, I had a very hard time getting the clamp back to its original height)
[www.calpoly.edu]

Before actually removing the AOS, time for a snack break. covered intake tubes with paper towels. Clamp still in place.
[www.calpoly.edu]

QUESTION: Finally got the AOS off, and this nastiness is found where the "middle tube" connected to it. Is this normal?
[www.calpoly.edu]

Comparing the old and new part. Some exterior differences visible.
[www.calpoly.edu]
[www.calpoly.edu]



Edited 1 time(s). Last edit at 04/03/2011 12:06AM by Steve (Berlin & LA). (view changes)

Good work!

Your old part ends in .00 and the new part ends in .01, so they must have "improved" it again.

That overflow tube is from the power steering reservoir. If you can identify the little pool of gunk as power steering fluid, then as long as your fluid level is okay, it's not an oil leak.

Regards, Maurice.

It was much more sticky. When I pinched and lifted a glob of it with my paper towels, little strands of it hung tight to the original pool of it like cheese hanging from a pizza slice. Is that what power steering fluid is like? If not, could it get that way by cooking on the engine for long times? Anyway, I'll check the fluid level tomorrow.

I'm gonna bookmark your post. Your stickers are terrific; they sure beat some goth skull and lightning bolt bs.