Blue smoke on start up - Page 2 - Porsche General - PistonHeads UK

Hi All, Got in my 996 c4s tip after work yesterday, when I started her up a cloud of blue smoke (lots of it) shot off out of the exhausts? started her up this morning and it done the same thing but not half as bad as yesterday, I also noticed vapour on both exhausts? The car has not done this before, and it was only given a clean bill of health from my indy on Thursday? Any help would be much appreciated.

jinster said: Hi All, Got in my 996 c4s tip after work yesterday, when I started her up a cloud of blue smoke (lots of it) shot off out of the exhausts? started her up this morning and it done the same thing but not half as bad as yesterday, I also noticed vapour on both exhausts? The car has not done this before, and it was only given a clean bill of health from my indy on Thursday? Any help would be much appreciated. Check its not been over filled with oil. If level is ok, take it for a good drive , get it properly warmed up and see if it smokes when warm as it shold not . See what its like the next day. Frank

jinster said: Hi All, Got in my 996 c4s tip after work yesterday, when I started her up a cloud of blue smoke (lots of it) shot off out of the exhausts? started her up this morning and it done the same thing but not half as bad as yesterday, I also noticed vapour on both exhausts? They all do that. It's a characteristic of the boxer engine as oil finds the lowest point. The air-cooled engines were even worse. If you have it under warranty, mention it, but It's usually nothing to worry about.

Lancerlot said: ...They all do that. It's a characteristic of the boxer engine as oil finds the lowest point..... True, but I've never seen a Subaru smoking like a wet bonfire on start-up!

It'll almost certainly be because the youngest mechanic ( are they still called mechanics ? ) in the Indy has road tested it and ragged it senseless. The engine will either implode or explode within the next 20 miles. Or ... it's because they all do that , I've read that it is possibly dependent on the actual positions of the pistons within the bores when the engine stops. Funny that it just started doing it.. as other poster suggested possibly overfill.

My car does it occasionally , maybe about 1 in 20 starts. A bit embarrassing none the less.

This is some times why its near impossible to get a consensus on forums. The post should be read and understood. We all know the 996 engine sometimes smokes but if you read the OP's post properly you will see: 1.It's not normally done it before. 2 It's now done it 2 days on the run. 3.It's just come back from a service. Does this sound like the normal 996 trait of smoking?? IMHO I dont think so. My 996tt will some times smoke. Once in a blue moon, normally when some one is watching. Very embarrassing. But the OP's problem reading what he has written does not sound right. Frank

Sounds like the AOS needs replacing

Need more info. Is it still doing it on (every) cold start up? Both exhaust or left only? Blue only or blue/ white?

It could be that the blinker fluid needs topping up!

s_mcneil said: Need more info. Is it still doing it on (every) cold start up? Both exhaust or left only? Blue only or blue/ white? I think your questions have already been answered by the OP..... jinster said: ...started her up this morning....... so too soon to answer if it's 'still doing it' jinster said: ....out of the exhausts?. note the plural jinster said: ....a cloud of blue smoke. so blue it is

Hi all, Like I said it has only started doing it. Had the car 5 months and have never seen it before. It is blue smoke, I think it comes from both exhaust pipes, lasts around 15 seconds then all is well. Does not do it whilst driving. If it helps you can smell ooil when it does it? The car went in to have the transfer box seal fixed that wad leaking on the tip box. Not leaking or losing angle oil, I think it coil be the AOS, however I have read that if the AOS has failed it should leak, but mine us not? Appreciate the comments that state they all do it, but like I said mine has never done it before. Car drives as it should, no obvious notice of loss of power etc....

jinster said: Hi all, Like I said it has only started doing it. Had the car 5 months and have never seen it before. It is blue smoke, I think it comes from both exhaust pipes, lasts around 15 seconds then all is well. Does not do it whilst driving. If it helps you can smell ooil when it does it? The car went in to have the transfer box seal fixed that wad leaking on the tip box. Not leaking or losing angle oil, I think it coil be the AOS, however I have read that if the AOS has failed it should leak, but mine us not? Appreciate the comments that state they all do it, but like I said mine has never done it before. Car drives as it should, no obvious notice of loss of power etc.... An earlier post mentioned the indy technicians taking for a 'test drive' and perhaps being a bit enthusiastic with the throttle. It is common for the exhausts to smoke the day after a 'spirited drive', mine does that. Maybe you haven't had the chance yet to really open it up, which is why you haven't seen this before?? I don't think you get leaks when the AOS has failed, the oil that normally gets sent back to the sump finds it's way into the inlet manifold, hence the blue smoke cloud.

General Bilko said: An earlier post mentioned the indy technicians taking for a 'test drive' and perhaps being a bit enthusiastic with the throttle. It is common for the exhausts to smoke the day after a 'spirited drive', mine does that. Maybe you haven't had the chance yet to really open it up, which is why you haven't seen this before?? I don't think you get leaks when the AOS has failed, the oil that normally gets sent back to the sump finds it's way into the inlet manifold, hence the blue smoke cloud. Hi Thanks for your post, but it did not do it when I picked it up on Thursday nor on Friday morning when I drove to work? Or am I missing something here?

Yep, sorry now I'm not reading your post fully..... You're right, if it was the 'test drive' you would have seen the smoke on Friday. Smoke on start up is quite common, and can be very intermittent for some. Maybe just monitor it for a while and see if it clears up. If it doesn't and a new AOS is needed the part itself isn't expensive but it is a long job (4+ hours), and longer with a tip I believe.

General Bilko said: Yep, sorry now I'm not reading your post fully..... You're right, if it was the 'test drive' you would have seen the smoke on Friday. Smoke on start up is quite common, and can be very intermittent for some. Maybe just monitor it for a while and see if it clears up. If it doesn't and a new AOS is needed the part itself isn't expensive but it is a long job (4+ hours), and longer with a tip I believe. +1 http://sites.google.com/site/mikefocke2/airoilsepa... Frank

General Bilko said: Yep, sorry now I'm not reading your post fully..... You're right, if it was the 'test drive' you would have seen the smoke on Friday. Smoke on start up is quite common, and can be very intermittent for some. Maybe just monitor it for a while and see if it clears up. If it doesn't and a new AOS is needed the part itself isn't expensive but it is a long job (4+ hours), and longer with a tip I believe. I don't mind if the AOS needs replacing, I was just worried that it maybe something more serious.

Update- just carried out the oil cap test, there is defiantly suction there when you try to open it with the car running. So faulty AOS I would pressure?. Can anybody tell me if the AOS would be covered by warranty?

Manufacturers or Aftermarket? (May have answered my own question if you've been to an Indy for the last work - that would've been covered by Manufacturers Extended warranty..........) Aftermarket? - IME any claim is extremely difficult to get through because of the wear and tear and lifetime of the part clauses.........

Update - when I now start the car it is not smoking, and is how it should be? I am really confused here. I had a leak on the tip box, that got fixed with a new sump pan etc fitted, basically the gearbox had a service. Could the smoke be down to the excess oil that needed to get to the sump pan which was lying around as such? PS - Used Ninex Motorsport in Maidenhead for the first time, Andy and his team are very knowledgeable and know their stuff!

jinster said: Update - when I now start the car it is not smoking, and is how it should be? I am really confused here. I had a leak on the tip box, that got fixed with a new sump pan etc fitted, basically the gearbox had a service. Could the smoke be down to the excess oil that needed to get to the sump pan which was lying around as such? PS - Used Ninex Motorsport in Maidenhead for the first time, Andy and his team are very knowledgeable and know their stuff! I don't wish to sound impolite, but why don't you put that question to Ninex Motor sport?

Trev450 said: I don't wish to sound impolite, but why don't you put that question to Ninex Motor sport? Because I only fired the car up when i got home after work and they have gone home for the day!

jinster said: Update- just carried out the oil cap test, there is defiantly suction there when you try to open it with the car running. So faulty AOS I would pressure?. Can anybody tell me if the AOS would be covered by warranty? There's a pressure difference which is normal. What is not normal is if after you unscrew the cap you can't remove it against the pressure difference. If this is the case it is a pretty strong sign the AOS is bad. If you can remove the cap against the pressure difference, though, this is *not* 100% proof positive the AOS is ok. An AOS can have 2 different failure modes (or have different stages arising from the same basic failure mode). Generally, if one starts the engine the smoking is there and continuous. The techs tell me -- and my experience backs this up -- they encounter smoking engines all the time. New cars and customer cars. The techs observe if the smoking is of a short duration and doesn't reappear after when the car is on the road, and there are no other untoward symptoms/behavior from the engine, the smoking is normal. Theoretically, it can arise from oil getting past the rings/pistons after the engine is shut off. This is a distant possibility, though. The most common path is the AOS is not very efficient, and this can be compounded by 1) the engine is overfilled with oil; 2) the oil is heavily contaminated with unburned gas and water (both happen and are normal) and this contamination can raise the oil level and make the oil more likely to foam/aerate which just compounds the AOS's inefficiency. Smoking upon start up results. But is should be short-lived and should not reappear as the car is driven. If you want remove the throttle body and check the body's bore and butterfly valve for the presence of oil. In the case of my Boxster that was undergoing a failing AOS, there was oil in the bore and in fact enough oil on the butterfly valve to form a droplet at the lower edge of the butterfly valve. Additionally there was considerable oil present at the connector opening right after the throttle body, the connector to which the hose from the AOS connects too. Plus the engine had a mild hesitation off idle which was 'cured' by cleaning the throttle body but the symptom soon returned. Sorry, but I do not know the conditions of your car's warranty, so I can't say if the AOS -- if it is bad -- is covered or not. Sincerely, Rockster.

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Hi, My 2004 996c4s also puffs out blue smoke on the left side for about 10 seconds.. it’s followed by white condensation smoke that’s disappears after a further 20 seconds or so.. I did a bore scoring check.. all ok.. still no idea why the blue smoke. Does only on startup first thing.. the car can be started approx 9 hours later and absolutely fine !