Smokey Joe

[DaveyB]

Hi,
Having owned a 996 for 5 weeks I am still getting to grips with all the quirks/faults etc. I took the car to work for the first time, and got the nice car/ flash git comments in equal measure. But the problem was when I left for the day. I started the car and a big cloud of blue smoke came out the back. It has done it once more since. Oil levels good, doesn't smoke under acceleration, and I have heard of this before, but what is it, and should I be worried?

Dave

 

[adrian996]

ORIGINAL: DaveyB
I started the car and a big cloud of blue smoke came out the back.

Hi Dave. Looks like you're relatively new to the concept of flat, horizontally opposed cylinders - as opposed to the traditional straight up and down type...?

These engines have something called an oil/air separator which can sometimes cause problems if they fail. But the result of this is more like clouds of white, oil-smelling smoke.

What I think that you have here is merely what is regarded as 'normal' symptoms of the positioning of the cylinders in your engine. I always get a cloud of blue smoke when my car has been 'at rest' for a few days or weeks. Its because small amounts of the oil in your engine finds its way past the piston rings when you car is stone cold. This is mainly due to the pistons laying flat and the metals being cold and contracted. It's also arguable that the standard 0/40w Mobil 1 oil viscosity (or lack of) doesn't help here either - the stuff is like water. This small amount of oil then ends up in the combustion chamber which then mixes with the fuel that you add with your foot and........BOOOM! Puff of blue smoke out of both tail pipes on start up which then fades pretty quickly(?).

So, pretty much normal behaviour for your engine (and all other 996's/997's). Only a problem if the smoke is white, you're using oil and she looks like a steam engine when she's under acceleration / power.

 

[DaveyB]

I know, I know, it's normal, but the cloud of smoke I got this morning made the road look like a war zone. It's not a good look. Do all 996's do this or just a select few?[&:]

 

[APS]

Mine did it on and off and to varying amounts, also depends if I park it on a slope etc. However since I had a major service mid April I havent noticed it at all.

 

[DaveyB]

Yea, had a minor servcie plus brake fluid at Harston porsche, and I didn't see any smoke for 10 days then I got the smoke this morning (after a bit of a thrash last night). It cleared straight away. Just have to hope next years major service sorts it.

Cheers
Dave

 

[DaveyB]

I thought the SAS were coming, the amount of smoke I had this morning. It did it once or twice when I first had the car but since having it serviced I have had two huge clouds of smoke. I notice when doing the oil level check the guage goes right to the top. Could it be over filled.

When arrivng at work this morning, I redid the check (24secs) and got the following reading, which is the lowest it's been since the service.

My concerns are -

1. It's bloomin embarrasing
2. Will it knacker the CATS

 

[Richard_Hamilton]

Is it blue smoke, or a huge cloud of white/grey smoke? Does it feel oily to the touch?

If it is white smoke, it may well be the Air/Oil Separator has failed. A simple check is to remove the large inlet hose to the throttle body, open the butterfly, and peek inside with a torch. If the internal surfaces are glossy with oily residue, then it is the AOS which has likely split internally.

 

[chrisbradley]

If it is the AOS, get it fixed asap - mine didnt just split - it exploded, and the engine had to be partly dismantled to clean it before fitting the replacement part !

Chris

 

[DaveyB]

Thanks Richard and Chris. Suspect this is the case.

And the cost of a replacement?

Is it a DIY job, or a book into the garage job?

Looks like a nice long weekend doing the discs and the AOS

 

[thirteeneast]

http://www.renntech.org/forums/tutorials/article/238-air-oil-separator-replacement-aos/
But I think the procedure is different for a 3.6

 

[Richard_Hamilton]

I think the proceedure is the same. Tiptronics are more difficult, I believe. The part is about £70+VAT, depending on model.

Not sure if it is mentioned in that thread, but you can loosen the engine mountings and drop the engine by a couple of inches to give better access. You have to be keen to DIY.

 

[steveoz32]

Strange, people always say they get smoke when starting if it is left. I started mine for the first time in four months to get it out for a clean the other week, and it started smooth as anything with no smoke and no noise!

Certainly smoke on acceleration isn't normal, it could as mentioned, be something as 'simple' as the AOS, whilst it is a simple bit of kit, changing it is not quite so simple.

Hows the oil pressure?

 

[DaveyB]

I am planning a weekend of pure porsche fixing fun. I have all the front disc stuff, and will get the AOS tonight/tomorrow. But just before I start removig the intake system and lowering the engine. I want to be sure it is what I think it is.

On two occasions I have had a massive cloud of white smoke come out of the back of the car when starting from cold. Instead of the slight blue smoke which I have seen
It clears after a minute.
The car runs fine, doesn't misfire, and no engine warning lights come on.
And subsequent starts, when warm, don't produce smoke.
It seems worse after I have been for a quicker than normal journey the night before.
And only happened after a service where the oil level gauge showed a level all the way to the top.
Tickover does drop slightly, momentarily, when removing the oil filler cap, but I would expect this for a dry sump under slight vacuum. Or am I wrong.

Ideas?javascript:void(AddText('[]'))

 

[gazzy]

Hope it's not a tip,had to have my AOS replaced recently and it's not a DIY job on a tip,and I did try before having to pay someone.

 

[Richard_Hamilton]

Did you look inside the throttle body?

 

[DaveyB]

I put a long knife with some tissue taped to the end and wiped it gently along the back of the throttle body, and got this. Which I thought was ok.

And then I stuck my finger in...

 

[DaveyB]

... and this just under (well slighty in a bit) where the butterfly would close...

So if this is getting long winded.

My Lotus Elised even waited 6 months before my first problem. So I'm still stupidly hoping it's just an oil level issue.

 

[Richard_Hamilton]

It looks dry, but a bit sooty round the butterfly, which I would say was fairly normal. Beginning to wonder about the AOS failure, although clouds of white smoke is typical.

What does the oil level show on the dipstick? If it is above the top mark, try draining some off.

 

[DaveyB]

Yep, checked at lunch time, and it appears by looking at the dipstick that the level is at the very top. I took a photo, but it is not very clear. Oil comes up to the waisted area and slighlty above.

When I did a dash oil level check, the reading was what it has been since being serviced at Harston.

 

[Richard_Hamilton]

It certainly is full, but difficult to say how much it has been overfilled. If it was me, I would try to drain about half a litre or so, and check that it comes within the markers. I always preferred to run mine with one empty bar below the max mark, rather than all full bars including the one above the max.