smoke on start up 996 3.6 - Page 2 - Porsche General - PistonHeads UK

I am getting quite a bit of white spoke on cold start up (just purchased car) its only done 54k 2001 3.6 full service history. is this to much fuel from auto choke! or could it be to much oil? Although it says that the oil level is fine. Once you have started it its fine no problems at all.. any thoughts.. should I be running round to a suitable garage!? Or is this a 996 bad habit.. Just for the record no mayo in the oil serviced about 1500 miles ago oil looks clear and clean..

Normal.

Should be normal - but depends on definition of normal, hard to say without seeing. For example, everyone said "normal" to that new Cayman owner recently whose car had 6.5k miles on the clock...that was new engine time (search for recent threads).

not always........ http://www.pistonheads.com/gassing/topic.asp?h=0&a... don't panic just yet though, it is a quirk of the flat 6 engine design-oil will seep past the rings whilst it's been sat & burn on start up. if you're worried get it looked at

Did you get the car inspected before purchase? If not, I would have someone look at it pronto...hopefully for peace of mind rather than discovery of anything sinister.

Thanks chaps, I like the idea of normal and will keep things under careful observation for a few weeks.. I suspect that last service monkey may have been a bit to generous with the oil which will not have helped... as for getting it looked at prior to purchase, I bought it of a guy in his late 60's early 70's one owner from new with every receipt and doc you could ever want and serviced 150 miles before I signed on the dotted line.. I may have been abit eager but sometimes you just have to go for it.. plus its stunning condition inside and out, but not to stunning!

outdoormax said: as for getting it looked at prior to purchase, I bought it of a guy in his late 60's early 70's one owner from new with every receipt and doc you could ever want and serviced 150 miles before I signed on the dotted line..plus its stunning condition inside and out That doesn't mean jack all to be honest in terms of whether your engine is on the way out or not - plenty of well kept and sympathetically driven 996s have had engine failures. Hope it works out ok though - might be worthwhile checking the oil level to ensure it's not overfilled.

coanda said: Check dipstick oil level aswell as electronic. It could have been driven hard and had a bit of oil slosh into the gas re-circ pipe. That got my attention for a few days! I have been giving her a bit of a work out! What is the gas re- circ pipe.. and is this a problem?

outdoormax said: I am getting quite a bit of white spoke on cold start up (just purchased car) its only done 54k 2001 3.6 full service history. is this to much fuel from auto choke! or could it be to much oil? Although it says that the oil level is fine. Once you have started it its fine no problems at all.. any thoughts.. should I be running round to a suitable garage!? Or is this a 996 bad habit.. Just for the record no mayo in the oil serviced about 1500 miles ago oil looks clear and clean.. Is the smoke oil smoke, does it have an oil smell? Or is the 'smoke' just water vapor? A bit of oil smoke upon start up is normal. However, 'normal' means the smoking is very brief, just an initial cloud, occurs infrequently (though other factors can affect the frequency... more on this in a moment), occurs at startup and never at other times, and the engine should not exhibit any other untoward behavior. Factors that increase the propensity of the engine to smoke: Too much oil; wrong oil; contaminated oil; short trips. A failing AOS can result in consistent oil smoking upon startup though this usually persists after startup. It wouldn't be a bad idea to have the car looked at by an expert on these cars just to make sure nothing's amiss. Sincerely, Rockster.

Thanks for your messages guys, I think I will drop it round to the local Porsche specialist just for piece of mind! all the best Max

Another thread on a smoky 996 3.6... outdoormax said: .. I suspect that last service monkey may have been a bit to generous with the oil which will not have helped... Is that not potentially really bad for an engine?

When you say "white" is it realy white or blue-ish or dark smoke?

cragswinter said: don't panic just yet though, it is a quirk of the flat 6 engine design-oil will seep past the rings whilst it's been sat & burn on start up. ^^^^ Yup!

monthefish said: Is that not potentially really bad for an engine? In extreme cases it is not good. Absent the extreme cases though the concern about overfilling a modern Porsche engine comes from the inability of the oil level sensor to report how much too much oil is in the engine. Which means I guess that one can't know if his engine's overfilled condition is just a mild case of overfilling or an extreme case of overfilling. If the oil level display has the segment above the max. line lit one can't know if the engine has approx. a half a quart too much oil or way more too much oil. Of course if one has an older model car that has a dipstick one can use this to determine the degree of overfilling, but for many owners the electronic oil level display is all the car came with. The best course of action is to simply not overfill the engine with oil in the first place. There is no excuse for an engine to be overfilled with oil. This is such a basic maintenance procedure at the professional mechanic level that if one takes his car to a professional and the oil level comes back too full he should find another place to have his car serviced. If one is doing the oil/filter service himself and overfills the engine, he should give up DIY oil/filter services and take the car to a professional. Sincerely, Rockster.

I am having the same problem, white dusty white smoke on startup. It lasts for a few seconds then disappears. The smell of the smoke resembles the smell of a choked car, very un burnt petrol smell. Car runs rock solid, no noises or faults. The only thing Porsche have picked up on is a slight damp spot on the RMS, they have said this is nothing to worry about yet!!! They still gave this a green light in the last major service. Anyone with any ideas? Tim

As a poster has said it can be as a result of too much oil and any excess is running down the bore when the car is idle. This the blows out. However, the bores need lubrication and this oil can run both ways when the engine is stopped. Unlike most normal cars the Porsche has horizontal bores so any excess either drains towards the sump or runs towards the pistons. For example if you always park your car at the kerbside (passenger door in)and the road has a steepish camber the left cylinder head is the lowest point above the bore. Any excess oil will run in this direction. If the car has been left in this location for several days, on start up the left exhaust will blow some white smoke. Before you go digging make sure that the oil level is right and NOT above the high mark on the dipstick. Try and park your car so that it is level from side to side. See if it smokes on start up. I suggest you do this first before changing the AOS. I changed mine recently as a precaution as some other things were being done. I understand that if they fail the smoke issue is quite significant.

The car is parked in the garage every night, level, I can start the car 20 times and it does not smoke. Then yesterday I cleaned the car, took it out for a run " reasonably hard" and let the the engine cool on tick over. Car stood level for 20 min or so, started car to back into garage and PUFF. For about 20 secs, from each exhaust, again it smells like unburnt fuel. I can only explain it as, like when old cars exhaust smells when started with choke full on. Used the car today, smoked on early morning start been ok since warmed up. Also do you think I should worry about the damp RMS? Thanks

Had mine 3.5 years and it always has a good puff of while smoke on start up. Gets used only about twice a week and covered 12k miles in that time, car runs perfect, so I suspect it's 'normal'

Bossitt said: The car is parked in the garage every night, level, I can start the car 20 times and it does not smoke. Then yesterday I cleaned the car, took it out for a run " reasonably hard" and let the the engine cool on tick over. Car stood level for 20 min or so, started car to back into garage and PUFF. For about 20 secs, from each exhaust, again it smells like unburnt fuel. I can only explain it as, like when old cars exhaust smells when started with choke full on. Used the car today, smoked on early morning start been ok since warmed up. Also do you think I should worry about the damp RMS? Thanks I know this is an old thread, but I’d be interested to know what the outcome was on this. I have the exact same symptoms on my 2002 4S(93k miles with a recent boroscope inspection showing no issues). The car does get used for short runs however. Thanks, Steve

Hi despite all the scare mongering on this site,I would say White smoke is condensation.The exhaust holds lots of water vapour, which expands drastically when you start the car. The smoke could linger a while, if it is just condensation, where as borescore smoke is Blue and will be mostly left exahust and will go after a few seconds. Chris

anonymous said: [redacted] If it's blue, I would agree.

My 80k mile C2 (previously reviewed by Mr Cmoose himself) does it after sitting when driven hard or after it's been sitting for a while without a drive. Nothing to worry about - all part of the fun of a flat 6 engine (so long as its not excessive). Also, if you aren't smoking after a long left hander you probably aren't driving it fast enough or you have a sump baffle. My 996 has fsh (recently from Porsche), a new AOS and RMS etc all done. My 997 GT3 also does it after its been sitting (albeit different engine).

Mine was doing it and it is the Air Oil Separator that is at fault. One way of diagnosing is by taking the oil filler cap off with the engine running. If there is noticeable suction on the cap and the smoke levels increase, then the AOS is the likely culprit.

outdoormax said: Thanks for your messages guys, I think I will drop it round to the local Porsche specialist just for piece of mind! all the best Max I too get a plume of blue smoke on my 996 C4s for 10 seconds on its first start up.. if I start the car again after 9 hours or so no smoke at all.. I’m going to get it checked incase of bore scoring.. it’s more of unburnt petrol smell than oil.. I might be wrong.. apparently it’s common .. 94k miles 2004