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I noticed white / blue smoke comes out at cold startup I went to the dealer to diagnose the problem and told me that AOS must be changed, So AOS has been replaced but smoke still continues to come out morning or when the car parked few hrs.

I went to the dealer again and told me the reason for the smoke is a large amount of residual oil in the exhaust/mainfold, Now more than two weeks and still I notice white smoke coming out from both tailpipes , but it disappears after 20 or 30 seconds، I opened throttle body and I saw some oil inside vent line and the plenum.

No noise coming from engine

carrera 4s 139k km 2006

Any advice or help thank you

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It is not at all uncommon for there to be residual oil and smoke after replacing a blown AOS. Problem is that over a period of time, a failing AOS can coat a lot of surfaces in the intake system with oil, which does not go away quickly. Some owners have had to resort to manually cleaning out their intakes to eliminate this problem. Not a fun job, but if the amount of oil is considerable, it may be you only option other than living with the smoke until the residual oil eventually vaporizes.

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It is not at all uncommon for there to be residual oil and smoke after replacing a blown AOS. Problem is that over a period of time, a failing AOS can coat a lot of surfaces in the intake system with oil, which does not go away quickly. Some owners have had to resort to manually cleaning out their intakes to eliminate this problem. Not a fun job, but if the amount of oil is considerable, it may be you only option other than living with the smoke until the residual oil eventually vaporizes.

JFP, just wondering. What would happen if you blew a bunch of combustible solvent into the intake before starting the engine, say ether. Could you not at least partially dissolve the oil? Once it gets down there the engine should burn it just fine.

My car always smokes for about 30 seconds on start up. I was told this was due to oil residue getting trapped in horizontal cylinders.

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My car also smokes on start up if it has been left for several days. Depending on "which side down" I leave it, that is the exhaust bank that smokes.

I liken it to my ageing brushcutter motorised lawnmower which also has a horizontal bore. If I leave the mower parked for a week or two with the cylinder head down hill it smokes on start up. If I leave it parked with the cylinder head up hill it does not smoke on start up. The reason is that the residual splash lubrication in the bore seeps past the piston and into the combustion chamber if it is parked cylinder head down. This is blown out on start up and takes about 30 seconds to clear.

The horizontal bores of the Porsche act in a similar way if one side slopes down for a long period at rest. The small amount of residual oil on the bores seeps past the piston and is then blown out on start up. This does not happen with a car that has vertical cylinders as the oil goes down and back to the sump.

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It is not at all uncommon for there to be residual oil and smoke after replacing a blown AOS. Problem is that over a period of time, a failing AOS can coat a lot of surfaces in the intake system with oil, which does not go away quickly. Some owners have had to resort to manually cleaning out their intakes to eliminate this problem. Not a fun job, but if the amount of oil is considerable, it may be you only option other than living with the smoke until the residual oil eventually vaporizes.

JFP, just wondering. What would happen if you blew a bunch of combustible solvent into the intake before starting the engine, say ether. Could you not at least partially dissolve the oil? Once it gets down there the engine should burn it just fine.

My car always smokes for about 30 seconds on start up. I was told this was due to oil residue getting trapped in horizontal cylinders.

Problem with blowing solvent into the intake is that it has to collect somewhere, like in the cylinders where it takes all the oil off the walls, which can cause scoring, or it collect in the oil sump. Either way, not good.

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It is not at all uncommon for there to be residual oil and smoke after replacing a blown AOS. Problem is that over a period of time, a failing AOS can coat a lot of surfaces in the intake system with oil, which does not go away quickly. Some owners have had to resort to manually cleaning out their intakes to eliminate this problem. Not a fun job, but if the amount of oil is considerable, it may be you only option other than living with the smoke until the residual oil eventually vaporizes.

JFP, just wondering. What would happen if you blew a bunch of combustible solvent into the intake before starting the engine, say ether. Could you not at least partially dissolve the oil? Once it gets down there the engine should burn it just fine.

My car always smokes for about 30 seconds on start up. I was told this was due to oil residue getting trapped in horizontal cylinders.

Problem with blowing solvent into the intake is that it has to collect somewhere, like in the cylinders where it takes all the oil off the walls, which can cause scoring, or it collect in the oil sump. Either way, not good

Excuse me JFP I should have been more specific. Using a spray can of ether, spraying enough for the vapor to just wet the walls of the intake then immediately starting the car. Not spraying so much that a significant amount could collect above the intake valve. This is another one of those how fast is fast enough questions.

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It is not at all uncommon for there to be residual oil and smoke after replacing a blown AOS. Problem is that over a period of time, a failing AOS can coat a lot of surfaces in the intake system with oil, which does not go away quickly. Some owners have had to resort to manually cleaning out their intakes to eliminate this problem. Not a fun job, but if the amount of oil is considerable, it may be you only option other than living with the smoke until the residual oil eventually vaporizes.

JFP, just wondering. What would happen if you blew a bunch of combustible solvent into the intake before starting the engine, say ether. Could you not at least partially dissolve the oil? Once it gets down there the engine should burn it just fine.

My car always smokes for about 30 seconds on start up. I was told this was due to oil residue getting trapped in horizontal cylinders.

Problem with blowing solvent into the intake is that it has to collect somewhere, like in the cylinders where it takes all the oil off the walls, which can cause scoring, or it collect in the oil sump. Either way, not good

Excuse me JFP I should have been more specific. Using a spray can of ether, spraying enough for the vapor to just wet the walls of the intake then immediately starting the car. Not spraying so much that a significant amount could collect above the intake valve. This is another one of those how fast is fast enough questions.

Problem remains that the amount of oil that builds up in the intake over a relatively short time is considerable, you can wipe it off the runner walls with your fingers and can often find little pools in places. There have been instances where a blown AOS has actually sucked enough liquid oil into the intake system to flood cylinders and cause a hydraulic lock to occur which bends or breaks very expensive parts. This is why we tell people with cars billowing smoke not to drive them, flatbed them to the shop. So with the potential for this amount of oil getting into the intake, I think you can understand I might be hesitant to believe that introducing a spray into the intake is going to clean it out on an assembled and running engine. We do use spray cleaners on the intake, but after it is off the car.........

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Do I have to worry more than that 950 km since aos replaced , Could this be because of the other symptoms ? Btw dealer still telling me smoke bcoz of old aos

It totally depends upon how much oil has gotten into the intake. We have pulled the throttle body off a car that was still smoking intermittently more than 1,000 mile after someone had replaced the AOS and dropped a bore scope down the runners, when we showed the owner what was still in there, he had us pull the intake and clean it.

Not all blown AOS lead to severe oiling of the intake; it depends how bad the AOS was, and how long the car was driven that way. A car that had a sudden but recent failure may have only a slight amount of oil in the system, but even that can take a lot of miles to clean out.

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Do I have to worry more than that 950 km since aos replaced , Could this be because of the other symptoms ? Btw dealer still telling me smoke bcoz of old aos

It totally depends upon how much oil has gotten into the intake. We have pulled the throttle body off a car that was still smoking intermittently more than 1,000 mile after someone had replaced the AOS and dropped a bore scope down the runners, when we showed the owner what was still in there, he had us pull the intake and clean it.

Not all blown AOS lead to severe oiling of the intake; it depends how bad the AOS was, and how long the car was driven that way. A car that had a sudden but recent failure may have only a slight amount of oil in the system, but even that can take a lot of miles to clean out.

Thanx JFP. I would assume that if enough oil was introduced into the intake to cause serious trouble that the oil level in the crankcase would drop enough to be noticeable on our stupid electronic gauges. Might the best approach be to monitor your oil level closely? The combination of persistent smoking and an oil level drop should certainly raise concern and a flat bed ride.

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Do I have to worry more than that 950 km since aos replaced , Could this be because of the other symptoms ? Btw dealer still telling me smoke bcoz of old aos

It totally depends upon how much oil has gotten into the intake. We have pulled the throttle body off a car that was still smoking intermittently more than 1,000 mile after someone had replaced the AOS and dropped a bore scope down the runners, when we showed the owner what was still in there, he had us pull the intake and clean it.

Not all blown AOS lead to severe oiling of the intake; it depends how bad the AOS was, and how long the car was driven that way. A car that had a sudden but recent failure may have only a slight amount of oil in the system, but even that can take a lot of miles to clean out.

Thanx JFP. I would assume that if enough oil was introduced into the intake to cause serious trouble that the oil level in the crankcase would drop enough to be noticeable on our stupid electronic gauges. Might the best approach be to monitor your oil level closely? The combination of persistent smoking and an oil level drop should certainly raise concern and a flat bed ride.

When the AOS totally fails and the vacuum jumps from 5 inches of water to over 20 inches, it can start pulling a lot of oil very quickly. And, as oil is not at all compressible, any volume larger than that of one cylinder head combustion chamber and piston valve relief volume (combined less than 100CC total) is enough to be fatal to the engine in one revolution. If that happens, neither the driver or the dash display would be able to react fast enough to be useful. So if it starts smoking, the safe bet is a flat bed.

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Do I have to worry more than that 950 km since aos replaced , Could this be because of the other symptoms ? Btw dealer still telling me smoke bcoz of old aos

It totally depends upon how much oil has gotten into the intake. We have pulled the throttle body off a car that was still smoking intermittently more than 1,000 mile after someone had replaced the AOS and dropped a bore scope down the runners, when we showed the owner what was still in there, he had us pull the intake and clean it.

Not all blown AOS lead to severe oiling of the intake; it depends how bad the AOS was, and how long the car was driven that way. A car that had a sudden but recent failure may have only a slight amount of oil in the system, but even that can take a lot of miles to clean out.

Thanx JFP. I would assume that if enough oil was introduced into the intake to cause serious trouble that the oil level in the crankcase would drop enough to be noticeable on our stupid electronic gauges. Might the best approach be to monitor your oil level closely? The combination of persistent smoking and an oil level drop should certainly raise concern and a flat bed ride.

When the AOS totally fails and the vacuum jumps from 5 inches of water to over 20 inches, it can start pulling a lot of oil very quickly. And, as oil is not at all compressible, any volume larger than that of one cylinder head combustion chamber and piston valve relief volume (combined less than 100CC total) is enough to be fatal to the engine in one revolution. If that happens, neither the driver or the dash display would be able to react fast enough to be useful. So if it starts smoking, the safe bet is a flat bed.

Thanx JFP, You should be a doctor. You have the hang of negating any risk. Now, all of my cars have smoked initially on start up. This usually clears in 30 seconds or so. How would you differentiate between this and pathologic smoking. Excuse me for being dim witted but I have never had a car do this to me (hopefully never). The car just starts smoking on the road?? How do people usually notice thay have a problem?? I have seen old cars that have a severe oil burning issue (bad rings?) and they puff blue white smoke most noticable at a stop. If I were driving along on the highway at 80 miles an hour and my AOS went what would happen?? (other than hydrolock and bent connecting rods)

Edited by Mijostyn
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Do I have to worry more than that 950 km since aos replaced , Could this be because of the other symptoms ? Btw dealer still telling me smoke bcoz of old aos

It totally depends upon how much oil has gotten into the intake. We have pulled the throttle body off a car that was still smoking intermittently more than 1,000 mile after someone had replaced the AOS and dropped a bore scope down the runners, when we showed the owner what was still in there, he had us pull the intake and clean it.

Not all blown AOS lead to severe oiling of the intake; it depends how bad the AOS was, and how long the car was driven that way. A car that had a sudden but recent failure may have only a slight amount of oil in the system, but even that can take a lot of miles to clean out.

Thanx JFP. I would assume that if enough oil was introduced into the intake to cause serious trouble that the oil level in the crankcase would drop enough to be noticeable on our stupid electronic gauges. Might the best approach be to monitor your oil level closely? The combination of persistent smoking and an oil level drop should certainly raise concern and a flat bed ride.

When the AOS totally fails and the vacuum jumps from 5 inches of water to over 20 inches, it can start pulling a lot of oil very quickly. And, as oil is not at all compressible, any volume larger than that of one cylinder head combustion chamber and piston valve relief volume (combined less than 100CC total) is enough to be fatal to the engine in one revolution. If that happens, neither the driver or the dash display would be able to react fast enough to be useful. So if it starts smoking, the safe bet is a flat bed.

Thanx JFP, You should be a doctor. You have the hang of negating any risk. Now, all of my cars have smoked initially on start up. This usually clears in 30 seconds or so. How would you differentiate between this and pathologic smoking. Excuse me for being dim witted but I have never had a car do this to me (hopefully never). The car just starts smoking on the road?? How do people usually notice thay have a problem?? I have seen old cars that have a severe oil burning issue (bad rings?) and they puff blue white smoke most noticable at a stop. If I were driving along on the highway at 80 miles an hour and my AOS went what would I happen?? (other than hydrolock and bent connecting rods)

OK, just about everyone knows that horizontally opposed engine designs like Porsche puff a little smoke now and then at start up; we laughingly call it "a feature of the car", and so it is. The difference is that when the AOS starts on its way out, the start up smoke tends to become more of a regular occurrence rather than the once in a while thing. The smoke also tends to become more pronounced at start up and lasts longer. When the AOS really gets bad, the smoke becomes a more frequent occurrence, usually at times other than start up, and very pronounced during high manifold vacuum (e.g.: steady cruise, downshifting as you approach a corner or stop light, etc.) when it can look like you are spraying for mosquitos, and sometimes accompanied by what driver's call a shrill squealing sound coming from the engine. These are definite signs the AOS is toast. In your hypothetical "driving at 80 miles an hour", the loss of the AOS would result in you not being able to see anything but white smoke in your review mirror.

Fortunately, you can quickly check to see if the AOS is going away. The easiest test is to try and remove your oil fill cap while the car is idling (a high manifold vacuum period), if the cap comes off and the car's idle drops off or becomes rough, the AOS is fine. But if the cap is very difficult to remove (as sign of very high vacuum in the sump), the AOS is going or gone. A more scientific approach would be to buy a spare oil cap and a 0-30 inches of water vacuum gauge (about $25-35) and mate the two by drilling the cap to accept the gauge and using a little epoxy to seal them together. A good AOS would show about 5 inches of vacuum or less at and idle, a bad one would be more in the 20-25 inches of vacuum range. We built a couple of these for the shop to test every car we work on; you would be surprised how often we catch an AOS in the early stages of "buying the farm".

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Wonderful reply JFP. I'm going to go out and get the parts for my vacuum gauge tomorrow.

Just be sure the gauge is calibrated in inches of water, not mercury (Hg).

No sweat JFP. Inches of water it is. It is only inches of oil if you fill the manometer with oil but that would mean we would need a bigger gauge and it already looks quite comber some. But it is simple and cheap. I bet some one makes a small aneroid (dial) version that would work well and be a lot smaller, easier to use and store. I'll hunt the net and see what I can come up with.

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Aneroid vacuum gauges are all over the place and they sell for around $15 - $20. They are all calibrated in inches mercury (hg). An inch hg is equal to 13.6 inches H2O. This makes the mercury manometer much less sensitive and harder to read but it will work. You would just test your gauge with your normal running engine understanding that when the AOS goes the reading will increase 2 - 3 fold or higher. Which with a mercury manometer is not much, 0.3 to 1.0 or above.

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Aneroid vacuum gauges are all over the place and they sell for around $15 - $20. They are all calibrated in inches mercury (hg). An inch hg is equal to 13.6 inches H2O. This makes the mercury manometer much less sensitive and harder to read but it will work. You would just test your gauge with your normal running engine understanding that when the AOS goes the reading will increase 2 - 3 fold or higher. Which with a mercury manometer is not much, 0.3 to 1.0 or above.

You can get inches of water vacuum gauges from lab supply houses, the ones we have are from Cole Palmer:

68357_04.jpg

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JFP, I went to Cole-Parmer's web site and found gauges in everything but inches water most of them costing over $500. Do you know where that one comes from? I'll continue to cruise and see what I can find. There is always Logray's contraption. Perfectly accurate just bulky.

Aneroid vacuum gauges are all over the place and they sell for around $15 - $20. They are all calibrated in inches mercury (hg). An inch hg is equal to 13.6 inches H2O. This makes the mercury manometer much less sensitive and harder to read but it will work. You would just test your gauge with your normal running engine understanding that when the AOS goes the reading will increase 2 - 3 fold or higher. Which with a mercury manometer is not much, 0.3 to 1.0 or above.

You can get inches of water vacuum gauges from lab supply houses, the ones we have are from Cole Palmer:

68357_04.jpg

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Today I saw oil measure before startup was less than bar and was blinking , I went quickly to the dealer and they said that is very normal you have to add 1 ltr every 1000m so they added 1 ltr

Now every startup a puff of smoke like small cloud from the pipe

Is this normal ? Do I have to worry

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Today I saw oil measure before startup was less than bar and was blinking , I went quickly to the dealer and they said that is very normal you have to add 1 ltr every 1000m so they added 1 ltr

Now every startup a puff of smoke like small cloud from the pipe

Is this normal ? Do I have to worry

Porsche describes the consumption of a liter per 1K miles as "normal behavior"; but smoke at every start up is not. Get your AOS checked.

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