One last try or I sell

[911hillclimber]

Close to the end of my tolerance to my 2.9 Boxster, 897.2 due to smoke on cold start. I ask this (again) incase anyone can suggest a solution once and for all.
If not, time to move on, TT or SLK, anything with a vertical engine!
History:
Occational heavy oil smelling and large smoke on cold start and today after 2 hours after a good run, less but the same smoke on 'hot' start.

2009 2.9 987.2, Porsche, PCT, Zuffenhaus service history all correct, now 58400 miles.
AOS changed by Zuff a year ago (not sure the old one was broken).
Car runs a dream clean, strong and without flaws.
Parked on the front of the house on flat drive, left to tick over for 20 seconds before switch off.
Last 3 starts I've had the big cloud on start up, never done this before, previous start smoke was random.

Car is not run for 2 mins and switched off, uses no oil, oil level indicator shows full.

I expect to do a north Yorkshire week run soon which will bring the car to it's 60K mile service interval which will be done at Zuffenhaus in about a months time.

I have NEVER seen a Boxster smoke on cold start in person, but mine cannot be the only one?
Any suggestions welcome, just about come to the point where I don't want to use it for fear of a smoke filled start, so pointless having this car.

 

[jdpef356]

Smoke on start up? I'm not saying it is but a common cause of this problem is right foot on the accelator pedal.

Try! Stand outside the car and turn the ignition key. Still got smoke?

 

[Roger Goode]

Surely the pleasure of driving your Boxster is the only purpose you need for owning it. You certainly wouldn’t get the same pleasure from an SLK or TT perhaps unless you bought a high performance version perhaps. You definitely would not feel the camaraderie and passion we have for Porsche.
My 987.1 Boxster S 44k miles and 996 3.6 Coupe 84k miles, both occasionally smoke heavily. I know it can be embarrassing if anyone else is around. Neither need topping up between the annual services I choose to have nor is there as far as I’m aware any problem with the AOS. The independent I use say that nothing is amiss.
As far as I’m aware it largely depends on where the pistons come to rest, allowing small quantities of oil to seep into the cylinder bores, I believe it’s something that happens with all flat engines. It isn’t a reason for giving up such a great car.

 

[911hillclimber]

Thank you both for your comments.
Starting is clutch down hard, no pressure on accelerator and turn the key.
My heart stops for a few seconds while I stare into the read view mirrors looking for the smoke after maybe 3 seconds as the smoke makes it's way through the silencer etc.
Or does not. Random but the occurrence is getting more frequent.

When clear the car is indeed fabulous.
I had a 2009 new shape (for then) BMW Z4 before this Boxster which was awful in comparison on several fronts, esp the stupid ride harshness, 201 bhp was poor but it never smoked...

I hope some others will chip-in with some comments as to their experiences and fixes.
I am lucky to have 2 other flat sixes, both 1985 3.2 engines, one is at least 170,000 miles in and has never been apart, no smoke.
Other is a freshly rebuild engine in the race car, thrashed to death and does not smoke.

This Boxster engine is a backward step on this issue. How could Porsche sell a car with this weakness?
I've been with Porsche for 30 years and fully understand the 'family' feeling!
Other ideas please?

 

[911hillclimber]

Just watched a vid on Google about this, I thought I had looked at all of them, but this is new.
The car is a 2.9 Cayman in the USA.
In the video, the owner tests the AOS by having the engine running and removing the oil filler cap (blue one under the cover in the boot) and if the cap tries to snap closed due to a vacumm in the engine the AOS has failed.
Is this true?
Mine snaps closed as I remove the cap engine running...
I've never read this way of ascertaining if the AOS is broken before. The AOs on my car is 12 months/ 6 K miles old.

 

[Motorhead]

Yes, I believe that's correct Graham and is a good indication of an AOS failure. I'd definitely get Zuffenhaus to check it out thoroughly.

Jeff

 

[911hillclimber]

Thank you for that, the suction is very strong.early 60k service coming up!
graham.

 

[blue99]

Hi what your describing is injector drip
worn injector nozzles drip on start up causing white smoke
excessive fuel is black smoke. Worn nozzles cause white smoke.
‘Hope this helps

 

[911hillclimber]

Thank you, that is a new one to me!
I'll look into it, 6 new injectors does not sound good!

 

[C2dweller]

I have a few customers with similar persistent symptoms. A simple thing to try before performing engine wear checks is to:
>use mobil 1
>ensure oil level is no higher than half on the scale.
I don’t believe either of the above makes any real sense but a recipe I’m told is proven to work.

I hope it keeps you in the fold!

Kind Regards Lee Jones

 

[911hillclimber]

Thank you, I have pondered the oil level several times.
If I fill my 3.2 engine more than 1/2 way between max/min the engine will give white smoke, I am sure this is the oil getting into the inlet due to volume in the system.
Totally different engine/ lub system to the Boxster, but when I did over fill (still under Max on the stick) I had the smoke while driving, not on start-up.

The Dempsey book '101 things to do on your Boxster' also says a high crankcase vacumm indicates a broken AOS, BUT there is a light vacumm normally, the high vac is about 4 x that normal negative pressure.
I have never read that a lower oil level will cure the smoke issue, but if overfull then the bore(s) could be puddled with oil and hence oil seeps to the bore...?
However, the last service was done by Zuffenhaus and they know how to do these things.
The handbook states the oil should be all bars black for correct level.

After fitting the new AOS 12 months ago by Zuff the smoke stopped, it has slowly become more frequent since the long Italian trip in May this year.
Plan is to get a fresh AOS from OPC tomorrow and fit it Friday.
The 987.2 AOS fitment is quite easy compared to the 986 nightmare of awkward pipes.

This is the ONLY thing that is a negative on this car and it is spoiling the ownership for me.

 

[Motorhead]

Graham,

I think replacing the AOS (again!) is definitely worthwhile as the symptoms indicate that this could well be the source of the problem. Maybe Zuffenhaus could open-up the current item to see if there's internal damage and if so at least that would give you peace of mind that that's what has been causing you the aggravation all this time. Get them to double-check the integrity of associated pipes/connections, etc.

Hope finally you get a positive and lasting result.

Jeff

 

[911hillclimber]

I hope so too!
going to local OPC now to buy another, OPC cheaper than eBay...
going to fit it myself on Sunday so can check all the hoses then and after split it open to see if the diaphragm is split.
will report back when done.

 

[carnaby35]

Did have this with my 3.4 987 gen 2 Boxster 26k miles but only once when parked overnight at a hotel with car sloping side to side. Lots of smoke on startup then cut out and wouldn't restart for about 5 mins.
never happened again so reckon it was the sideways slope. You apparently park level so shouldn't be that.

Chris

 

[911hillclimber]

Yes, parkingon a slope can produce thissmoke....
I have this on the level or slope, but the aos arrives tomorrow, fitting it on Sunday.
might have some residue oil in the inlet tract for a while until clear.
Looking forward to opening the current aos.

 

[AndrewT]

Looking forward to opening the current aos.

I’ll be interested in your report. When I opened the old AOS from my previous (smoking) 2.9 the whole thing was quite oily yet the diaphragm was intact.

Was it on these forums that I read a report from someone who’d somehow modified their AOS to stop the smoking?

 

[911hillclimber]

I went to the PCGB Region 13 Tech Seminar yesterday, and a specialist was discussing AOS on the water cooled cars and various thoughts were discussed.
On thought that several agreed with was the oil level in the car (and mine in particular).
The oil level has always been 'full', all the dash board 'bars' filled in.
However, this does not indicate over-full.
We discussed reducing the oil level to one bar below Full, ie one bar showing empty right at the top.
I am tempted to try this, syphon out a quantity of oil from the sump so the dash does show one bar down.
This could reduce the oil that puddles in a cylinder after a run and that seeps to the combustion chamber over time and thus the smoke on start-up?

If the current AOS is split then the part is covered under the Porsche 2 year guarantee, so I might get my recent money for the part back. Doubt that would include the labour to fit it!

The car is outside for this job, and it's raining!
Might have to do it tomorrow if dry enough, but I have the new AOS in the garage.

 

[Motorhead]

Graham,

Interesting to note that even the 'experts' don't have the answer to this problem. It could just be that oil is puddling in a number of cylinders when the car is stationary, maybe due to an unfortunate alignment of the oil control ring gaps.

Personally I can't see that dropping the oil level by one bar (0.4 litre?) on such a large sump is going to make any difference, but you're into desperate measures now, so it's worth a punt.

Jeff

 

[911hillclimber]

Yes, a lot of 'smokin mirrors' around white smoke and bore score etc explanations!

So, the AOS is swopped over.
Thought I would sketch out a few things during my virgin exploration of working on the dirty bits of a Boxster engine for those with the 987.2
Firstly, there is VERY little info on this model, loads and loads on the 986 and 987.1 but the .2 is still a rare breed. I found lots of the details between the 986 and the 987.2 are very different, but here goes:

1
Remove your belt of your jeans or be sure your overalls have no sharp items as you will be all over the paint on the NS of the car.
2
Erect the roof to about 12" from the screen header rail for best position to open the engine area up. The soft top cables (with the ball joints on them are not at the well of the body shell but just under the lower edge of the soft top frame and very visible. Took me a long time to discover their location.
There is a long strap velcrow'd to the frame to pull and keep tight the rear of the soft top, the loop on the free end hooks to the NS 'tab' that locates the soft top header rail to the screen header rail. If you haven't opened the roof wide enough the loop will not reach the tab!
The rail curtain is unhooked at 4 points and pulled back to expose more of the top panels of the engine cover.



Remove the top carpet from the engine bay and the access panel behind the seats and then the aluminium panels to expose the 'mighty' 2.9 engine!



The AOS is all but hidden and looked a nightmare, but there are just 2 screws to undo once you have pinched and removed the hose off it that leads to the inlet manifold. I stuck my finger in the released connection and there was oil in there...
The one screw is reached easy via the inside opening behind the seats, so did the easy one first and then set to for the other screw.
It is almost invisible as the roll hoop tube sits right over it and you have to lay right across the car to see anything. You need a 12" extension to a 3/8 socket drive and deep down more by luck I got the screw head and out it came, carefully.
The AOS module is then eased out of the engine block and then there is a hard hard part of actually getting it out of the car! What a game, be very patient.

New AOS was forced/pushed/twisted etc back in after oil on the O rings and the 2 bolts actually went in quite well and tightened down.
Refitted all the panels and clips and pull wires and cleaned the 2 drains at the wells on each side of the car that can block with debris etc over time. Flushed them through with a watering jug.

Started the car after putting the hood back up and it started smoke-free and ran well. Took it for a good run to get it hot and back on the level drive ran the oil level check, also the suction pull on the oil filler cap is much reduced and the engine stumbles far far more noticeably when you free the cap from the neck.:



Job done, watch the start of the GP and went to open the old (well, 12 months old) AOS. Prised it open to expose the diaphragm, the spring etc and the chamber where the oil condenses out of the engine air to drain back to sump and the passage that allows the residual engine air to pass to the inlet.


It is PERFECT inside! no splits or anything. Could not resist dissecting it ...



So, has all this been a waste of time? I think so, but it has crossed the AOS off the criminal suspect list.
Next step is to use the car and see what happens.
If it smokes on start-up I will look to drop the oil level, one bar below full.
Can you suction/syphon oil out of the sump via the filler neck tube?

 

[AndrewT]

You said "I stuck my finger in the released connection and there was oil in there...”

Where has that oil come from then, should it be free from oil in there?