extreme smoke by cold start when driven hard

[infinity]

Yesterday morning I went for a real blast with my 996 (2002 Carrera 4) and put it in my driveway after it. In the evening I started it and I had my whole street covered in white smoke. I only have this when I pushed it really hard, and then let it cool down. When I drive it normally and than put it away I don't have this problem. I read some things about this being normal, but it is starting to be a bit embarassing and since I am still in my warranty I would like to have it solved if this is possible. Anybody having an opinion on this? (By the way my oil level is 1/8th so I actually should give it a little oil.)

[turbobloke]

infinity said:

Yesterday morning I went for a real blast with my 996 (2002 Carrera 4) and put it in my driveway after it. In the evening I started it and I had my whole street covered in white smoke...By the way my oil level is 1/8th so I actually should give it a little oil.)

Hmmm. Been musing on your post for a few hours now, and still can't get away from the fact that a fair bit of oil is getting to where it can be burnt, smart eh



Have you taken off the air filter and had a poke around down there? Any oil? Is your 1/8th full really way more than that - dipstick or dial reading? Do both agree? Are you taking the reading with the engine warm and running, as if off and cold the oil drains back down giving a false low reading? Maybe a faulty oil level sender? You probably know more about 911s than me and are now cursing that you know all this...

The only time I had symptoms like that was when an independent unintentionally overfilled with oil at a service, one start-up was enough then the excess was drained. Symptoms disappeared quite quickly after that.

Even though it's only a problem after a blat it could still be something like this, here's a response to a FAQ on a 911 site "It's a good idea to fill the 911 tank to slightly below the max mark as on some models oil can 'spill' into the breather pipe when cornering enthusiastically"

Beyond that I gotta give in...cmon techies, chip in

[orpheus]

This happened to me exactly twice (2001 C2) - both times after an enthusiastic drive home from work.
At the time I thought it might have been related to parking sideways on a slope, but I'm sure it was actually down to overfilling - it hasn't happened again and I've done 10,000 miles since...

[grant3]

If it is simply a "puff" on start up then this is stated as normal, happens to me as well, looks worse than it is! If it is still blowing oil once running (& if revved) then it needs to have visit to your freindly OPC.

[abarber]

I've seen this happen from a C4S after starting up for each session at a track day. Seems normal after a really hard run?

[Dogsharks]

The 911 series cars are oil cooled, and even with the wasserpumpers, it's a good idea to let them cool for a while before shut down.

Running one hard and shutting it down (while hot) just allows things to cook down, regardless of whether they are turbos, oil cooled or water cooled.

I'm wondering if a car when run hard and shut down hot, will allow more oil to seep into valve stems. On some engines the valve covers (cam covers) will fill with oil when run hard (the Ford 427 is a perfect example, which requires some attention when running in a NASCAR or LeMans type event). Some engines develop internal pressure too, so with a valve/cam cover full of oil, while hot, using synthetic oil known to seep faster into tight spots, I suspect there is room for a smoker next time it's started. My high milage 944 smokes a bit when started due to seepage by the valve stems, with synthetic oil of course. Once started it runs clean and fast, no big deal.

Just a couple of comments to spark some additional thoughts.

Regards, Dogsharks

[GreigM]

Flat 6 engines, and particular the M96 (used in 996 and Boxster) are known for this. Basically ocassionally the ring gaps on a piston line up and let some oil into the cylinder. This then gets burnt on startup. Very normal and nothing to worry about.

However, this should only produce a puff of smoke on startup when cold, and never while warm & running. If it lasts for much more than 30s after the car has started then I'd get it seen to.

[infinity]

Thank you all for your reactions so far. It is only when cold and goes away after a minute running, so I think I have to get used to it. But when cold and blasted it before turning down it really is not only a "puff" but one big cloud. But it has no excessive oil consumption. I check the oil cold before starting. Good suggestion to check it manually as well, will do that. Thanks again.



>> Edited by infinity on Wednesday 20th October 16:11

[turbobloke]

infinity said:

I check the oil cold before starting. Good suggestion to check it manually as well, will do that. Thanks again

Sorry to come back on this but do you really mean that - you check the oil level with the car cold and engine off? Should always check with the engine running and the oil warm, on level ground. If you only check cold you will get an artificially very low reading and if you top up to even one-eighth when cold, it will be over-full by a long way in reality. On a blat you will then definitely get oil where it shouldn't be. If I've misinterpreted your post, then disregard this!

>> Edited by turbobloke on Wednesday 20th October 20:08

[Dogsharks]

Just another thought regarding turbocharged cars, in the event it's applicable to someone.

If a turbo bearing is going out, it will let a "LOT" of oil into the exhaust or intake side of the turbocharger, depending upon the design, and this could smoke a lot before the catalytic converter got hot enough to start burning the stuff off.

Dogsharks

[P15TON]

My 996C2 started belching great clouds of smoke about a mile after leaving home, even with the slightest touch of the throttle.
Returned it to the OPC@ Silverstone; they said it needed a new mass air flow sensor which they fitted under warranty.
It hasn't done it since.
I must admit, when I saw the smoke screen behind me, James Bond style, I did get a severe attack of (potential) wallet cramp!

[infinity]

turbobloke said:

infinity said: I check the oil cold before starting. Good suggestion to check it manually as well, will do that. Thanks again Sorry to come back on this but do you really mean that - you check the oil level with the car cold and engine off? Should always check with the engine running and the oil warm, on level ground. If you only check cold you will get an artificially very low reading and if you top up to even one-eighth when cold, it will be over-full by a long way in reality. On a blat you will then definitely get oil where it shouldn't be. If I've misinterpreted your post, then disregard this! >> Edited by turbobloke on Wednesday 20th October 20:08

Turbobloke, I mean checking with the digital device in my revcounter, I think the Porsche engineers kept your reply in mind and anticipated on this??