Does the 2.9 987.2 have an AOS?

[911hillclimber]

I am still irritated by the occasional oil smoke cloud on cold start, so sorry to open this topic again.

according to design911 web pages, the 2009/2012 987.2 has the same design of aos as the 986.
I did not think this was so.

question..
does anyone know if the aos could cause the oil smoke cloud on cold start?

 

[AndrewT]

Graham,
The 987.2 2.9 does have an AOS. My previous Cayman 2.9 suffered the same occasional smoke screen on start up. It was very difficult to recreate at will, but it was most likely to happen when the following sequence was followed: car was started, backed out of garage, switched off, left to stand for an hour, started, put back in garage, switched off, left overnight, started next day = blue smoke cloud.

I had the AOS replaced and a slightly heavier oil put in the engine. It did improve but not cure the smoke. My car never used any oil, but it’s embarrassing to have your car smoke like that.

I dismantled the old AOS for inspection, it was very oily both sides of the diaphragm. This led me to wonder whether there was still some oil residue left in the inlet manifold.

I had wondered about performing a test by directing the oil breather into a catch tank have first cleaned the AOS, just to prove to myself whether or not that was the cause of the problem.

I have since sold that car and bought a 3.4S, no smoke with that. It’s such a shame that the random smoke is detracting from your total enjoyment of the car.

Andrew.

These links may be of interest.....
https://www.pistonheads.com/gassing/topic.asp?t=1333670

https://type911shop.co.uk/epages/de867ca1-377e-432e-84fd-bdccf2206766.sf/en_GB/?ObjectPath=/Shops/de867ca1-377e-432e-84fd-bdccf2206766/Products/8169

http://www.renn-list.com/The-secret-behind-the-exhaust-smoke-upon-startup-2-9L-Caymans-An-inconvenient-truth_10573345.html

 

[911hillclimber]

Thank you Andrew, interesting to read.
I might change the aos just to see if it changes anything.
at £100 not too bad a cost.
the car might do its trick after a long journey so fully hot and the next day the smoke is there, or it will do nothing, or leave it for a week and smoke or do nothing.

I think the smoke frequency is increasing, but could be my heightened awareness...
graham.

 

[AndrewT]

the car might do its trick after a long journey so fully hot and the next day the smoke is there, or it will do nothing, or leave it for a week and smoke or do nothing

That pretty much matches my experience but after 2 years of ownership I worked out that the start/stop sequence I mentioned was the one that eventually enabled me to video the smoke.

The original owner reported the smoke to Porsche at about 57k miles but they did nothing as they couldn’t repeat it. I bought the car at 68k miles and sold at about 75k miles, the smoke didn’t get any worse but improved a bit with the new AOS so as you said, it’s worth trying for £100.

 

[Motorhead]

Graham,

In addition to the whitish smoke you can get a distintive screeching sound when the AOS is failing.

You'd need to check with Porsche to find out if the 986 and 987.2 use the same separator, but I doubt it.

Owing to the engine's boxer configuration oil can build-up readily in the bores only to be burned off when you start the engine, so a limited amount of smoking is quite normal. Also, if you're not using the car very much condensation will collect in the exhaust system leading to what might look like smoke on start-up but is actually water vapour, again with a whitish appearance.

Hope you get the problem sorted.

Jeff

 

[Richard_Hamilton]

My 2.9 was MY2012, so one of the last. I never had any smoking, even after the start/stop/overnight/start scenario. It never used a drop of oil between services either. The piston revision might explain that, or perhaps I was just lucky. My nephew used to have a 2009 997.2S which frequently did the smoke trick, and used about a litre of oil between services. There were 3 piston versions for that version of the 9A1 engine too.

 

[911hillclimber]

Thank you all.
nothing is simple!
design911 list their aos specifically for the 987.2
will ask OPC for their part too first.

 

[Motorhead]

Graham,

Just to add that you may well find that the part will be cheaper from the PC when you include the 10% Club discount. Plus you'll be certain to get the correct part.

As Richard has alluded to, there's enormous variability on the modern water-cooled engines regarding oil consumption and smoking on start-up. My own 2009 987.2 CS gets limited usage (circa 3k miles per year including some track-days) and I tend to get the water vapour thing on start-up but I've never needed to top-up the oil between services.

Maybe we should start a thread here on the subject to see if we can correlate some data?

Jeff

 

[Richard_Hamilton]

The latest part number is 9A1.107.042.02 and they are £66.77 incl. VAT at a Porsche Centre.

 

[911hillclimber]

Thank you both, I'll call into my OPC in Wolverhampton tomorrow and get one. That is £40 cheaper than Design911!

I expect fitting it is much like all the vids on youtube/986.
Never seem my engine, so first time for me! I've got small hands so may have an advantage, but short on patience!

As an aside, Des911 list an 'Oil Conducting Housing' for the 987.2, about £700. This goes over the top of the engine and has the oil filter at one end.
What exactly does that do?
Usually, these specialist supplier list parts that are commonly failing and need replacing, and thoughts?

As to getting a consensus on the cold start/oil smoke issue across this forum..I'll give it a try on a separate thread.

 

[911hillclimber]

Doing a google search on this topic, found this diagram, useful!
The AOS shown (#16) looks very different from the 986 early Boxster unit and the fitting looks very different where it is bolted to the engine / Oil Conducting Housing (#12).

Anyone on here actually changed a 987.2 AOS on their driveway with experiences to tell please?

 

[AndrewT]

Anyone on here actually changed a 987.2 AOS on their driveway with experiences to tell please?

Sorry Graham, I wimped out and got mine changed by a garage (not an OPC).

 

[911hillclimber]

I'm not too keen tbh to do it either, but want to try and also keep costs down incase it achieves nothing!
The diagram shows no hoses to the AOS, and the 986 is famous for the bottom hose connection which puts me right off. Hope the tech at the OPC will let me into his take on the task before I order the part.

 

[AndrewT]

I’m not sure if you’ll be able to see this, this is a video of my car after the AOS was replaced - the smoke used to be worse. I was able to film this because I was confident it would happen following the start/stop/start/stop/start sequence I mentioned.



https://m.youtube.com/watch?v=hGgQqJIa8V8

Hmm, doesn’t look like it works. I’ll try again when I’m on a proper computer rather than an iPad.

I think that link should work now.

 

[Motorhead]

Graham,

It looks as though item 12 could be the Oil Conducting Housing to which you were referring, item 16 being the AOS and item 3 the oil filter.

Thankfully I've not need to replace the AOS on my CS but I get the impression that it's not particularly difficult if you're a competent spanner man, just a bit fiddly.

A thought: before you buy a new AOS have you checked the inlet ducting downstream of the MAF to see if there's any significant oil contamination?

Jeff

 

[911hillclimber]

Video work, and my smoke when it happens is much worse than that!
I think I'm able to do it, just reluctant, but a bit of investigation would help, but it will now be something that needs to be done, just to cross it off the list.

 

[911hillclimber]

With some help from members on DDK forum, there is some clarity.

I am going to my OPC today to ask about fitting the AOS, but will ask if this DME upgrade has been carried out on my car in the past.

I heard this story from Steve Bull at April's Boxster 987.2 seminar but could not find further info on the web.
Could be very interesting!

Early 2.9's had Pistons with no oil scraper relief bores; this was cited as a possible cause initially. After more occurrences Porsche issued a DME update; essentially remapping the engine control which reduced the likelihood of it occurring (it opens the throttle when the motor is stopped effectively dumping any intake vacuum which had a tendency to pull oil from the breather system).

Check it's had the update

 

[911hillclimber]

Dropped into OPC Wolverhampton for a chat about the car, they could not have been more helpful.
Checked the car's history on the data base which has 'limited' depth but no record of this 'smoke' ECU update but there was an ECU update made in 2012 but the record did not say what it was...
Technician suggested a call to Porsche Reading (where the car came from new) for details.
Made that cal and explained to the receptionist the story, she promised to come back after talking to a few people.

This she did an hour later, and the car has not had this 'smoke' upgrade to the DME unit, all Recalls were done, but the smoke issue fix is a Service Action so some do not take it up.
Additionally, there is no record of it taking place in the big history file I have on the car, so I need to get this done now.

I will ask OPC Wolves to do it, but they might have to discuss with Reading as they seemed a bit vague about it in Service.
Still, encouraging so far.

Asked about the AOS and fitting it. It is different from the awkward 986 aos, it un-bolts from the oil conducting housing with one pipe at the top (accessible!) and 2 O rings, £67.
They suggested a new short pipe as the replacement is longer/easier to fit.

Plan is to get the ECU re-flash done and see what happens, if that does not fix it a new AOS.

Getting to the very bottom of this now. []

 

[Richard_Hamilton]

This is from the workshop manual about changing the AOS on a 987.2:

Preliminary work for removing oil separator
1. Move convertible top to service position.
2. Place protective covers on the vehicle to avoid damaging the body.
3. Remove engine compartment lid.

Removing oil separator
1. Disconnect oil filler pipe at the rapid-action coupling.
2. Remove crankcase vent line at distributor pipe and oil separator. To do this, release and pull off rapid action couplings.
3. Release and pull off rapid-action coupling on crankcase vent line.
4. Unscrew two Torx screws (M6 x 20).
5. Release spring band clamp and loosen hose carefully to turning it using a water pump pliers if necessary.
6. Pull oil separator up and out. Cover openings with a cloth in order to catch any drops of oil.

If anyone wants the section of the manual, with illustrations, drop me a PM with your email address.

 

[911hillclimber]

Richard, pm sent!
Graham.[]