Smoke Moan

[DaveyB]

Hi All,

I know this subject has been discussed several times, but it is really concerning me that there is no definitive answer or solution. I am talking about smoke on start up.

I have owned my 996 Targa for two years now. And every so often I get a period where I get smokety start ups, then nothing for a month or so. There is a huge cloud of smoke whiteish smoke (it's oil as you can smell it), and it clears straight away. I have had two instances where I have been pressing on really enjoyably and there has been a puff of james Bond style smoke for a second, but I believe this to be a separate issue, so I had my AOS replaced two weeks ago, as I thought this this must be the reason for both. However, smokey startups again after one week. This is the only thing that has spoilt my ownership of this car.

My concern is what is the real cause of these smokey start-ups, as there seems to be various ideas, which I have seen discussed on Renntech, Pistonheads, Pelican etc -

* AOS valve sticking - I've replaced mine and the same occurs.
* Warn valve guides allowing oil to seep past - Why do I not get smoke on every start up then?
* Piston ring location with split at the bottom allowing the oil to seep past - Again why not smoke on every start up?
* Oil too thin for an older engine - I changed from Mobil one 0/40 to Ultra 5w40. Still no difference.

Apart from a top end (well side end) rebuild is there anything I can try? My wifes using it as leverage to get me to sell the car and "buy something sensible"! I must fight back against this!!

Other than this the car really is a beauty.

Help
David

 

[tazza_no1]

Hi Dave,
Try a worm up and cool down each time you drive the car.

Warm up
Start the car, do not rev and allow the engine to come down to normal idle before driving off or revving. Avoid revs over 3500 before the engine hits at least half of normal temp.

Cool down
After a drive, don't turn the engine off straight away.
Allow the engine to idle for 2-3 minutes before switching off. This will allow any oil that has gone into the exhaust to be burnt off without giving you a cloud of smoke.

Try it for a week and see how you go.

 

[s999sws]

my cayman sometimes does this, I was told by Exeter OPC that it probably is oil seeping past the piston rings, which CAN MOVE, so that the gap moves around.
this does make sense to me, so I'm quite happy with this reason.
cheers
steve ws

 

[tscaptain]

David,
What you omit to say is how much oil is being consumed. If you are not putting undue amounts in then I would think that it's all normal for these engines. I had a 997 which always puffed on start up and used about 1L per 1500 miles (within the normal range). The current car doesn't puff on start at all and doesn't use a drop between services. They do seem to vary a lot. I also agree with the seepage past the piston ring theory![]

 

[tim92gts]

No problem on ours but i run on 10W-50 with a bit of ZDDP in, cats all fine. It doesn't use any oil so nothing gets out to burn in and contaminate them.

The 928 puts out a little smoke almost like dust when i floor it for the first time in a while, suspected as being due to a bit of oil collection in the manifold being flushed out by WOT airspeed.
Tim

Still got a Suzuki (Jimny) so i expect you noticed a change when you upgraded to the 996!

 

[DaveyB]

My car uses hardly any oil. I guess it's about a litre every 7 to 8k miles. I don't think that is too much at all. So little I really haven't taken much notice. I am currently trying the warm up cool down method suggested by Tazza_No1. And it's been fine for the last couple of days. It's hard to say whether this will work because I've gone for about 6 weeks without a problem before.

I do think the piston ring theory could be close. I just need a button on the dash that points the gap upwards when I turn the engine offjavascript:void(AddText('[]')).

I also what issues I would have if I ever have to sell the car. Try explaing to someone "oh it's just the piston rings moving".

 

[tscaptain]

ORIGINAL: DaveyB


I also what issues I would have if I ever have to sell the car. Try explaing to someone "oh it's just the piston rings moving".

"But they all do that, Sir"[]


Anyhoo, if you're only using a litre every 7-8k I don't think you have any major (or minor, for that matter) issues.

 

[Richard_Hamilton]

I think I've said this before, but....

Under normal use I don't have the puff of smoke at start up. However, I guarantee I can make it happen, depending on events immediately prior to shutting down the engine. If I arrive home, and drive the car straight into the garage and shut down, I will have no smoke in the morning. If I park it on the driveway, and put it in the garage an hour later, it will give a puff of smoke the following morning. Similarly, if I get the car out of the garage, give it a wash, and put it away, I'll get a puff the next morning. My 993, 996, 996T, 3.2, and Cayman all do/did the same.