Hello to all 

Mine is mk8 1.0 ecoboost 100ps 6 speed automatic, 2019 - current mileage is 14.5K miles

Yesterday this issue happened to me and I'm extremely worried, The car was idle for about 15 minutes with AC turned ON, I was setting inside, suddenly there was engine shudder or shaking ( single shake as if its a temporary misfire ) just a single one, I looked instantly at the rear view mirror ( immediately as if I know that there is something coming out of the tail pipe, I don't know why 😄 ) and yes I noticed white smoke coming out of the tail pipe, I tried to capture it on the attached video, I gave it a single rev up to 4k RPM and there was more smoke, and then suddenly the smoke stopped , since then nothing else happened !!

No lights on the instrument cluster, no messages, no abnormal engine behaviour, oil level OK to the MAX, coolant level OK to the max also, car drives sweet as nuts !! I can't figure out what really could have happened !!

Any body experienced such a thing before ? what could it be ?

I have read somewhere on the brands forums that it might be valve stem seals about to fail, others pointed out that it might be the turbo bearing going bad, others say its completely normal as turbocharged engines from time to time burns oil that sits somewhere inside the intake pipe !! other people also say that its a normal process called  catalytic converter regeneration (which I have no idea what it might be 😄 ) and it happens from time to time but as you drive you don't notice it !!  

I'm completely confused and I'm interested to hear from you 🙂 

Thank you very much for considering 🙂 

 

I don't think this is anything to worry about. Some condensation that builds up in the exhaust would get blown out slowly as you drive at speed and you would not notice it. Sitting at idle for 15mins has allowed it to build up and when cleared it generated some back pressure that caused rough running.

What was the car driven like before being at idle?  

I would try and repeat the driving and idling conditions to see if it happens again. It might be difficult to repeat the problem.

The MK8 has a GPF (Gasoline particulates Filter) which according to the drivers manual says it purges the filter from time to time, could it have been that?

I have no idea what to expect when a GPF gets purged so just another possibilty to look into.

 

57 minutes ago, Blatto said:

The MK8 has a GPF (Gasoline particulates Filter) which according to the drivers manual says it purges the filter from time to time, could it have been that?

I have no idea what to expect when a GPF gets purged so just another possibilty to look into.

 

This is the answer to your problem Ahmed: "As with any type of filter a Particulate Filter needs to be cleaned regularly to function properly. With GPF’s this is done by a process known as Regeneration which involves a combination of a catalyst function in the system and burning the soot to gas at a very high temperature leaving behind an ash residue within the PPF. Regeneration should be an automatic process taking place in the normal use of your vehicle. You may have noticed this in the form of a blast of white smoke form the exhaust on occasions."

This might be useful.

For regeneration to take place it requires the vehicle to be driven regularly at some speed on open roads e.g. motorway driving, typically driving at around 2500 RPM for approximately 15-30 minutes at least twice a month. This should keep things working. Many Petrol vehicles are used primarily in urban areas or for short stop start journeys, school runs etc as a diesel alternative and many have an auto gearbox, so the vehicle does not get the chance to heat up sufficiently and is unable to carry out a full regeneration process. Even if the regeneration functions as it should, over time the ash residue will build up in the PPF and have the same affect, ultimately resulting in a blocked PPF. For this reason a PPF is classified as a serviceable Item by the vehicle manufacturers like brake pads or air filters, and not covered under warranty. PPF systems therefore need to be maintained properly, or a solution found when they fail to work correctly.

I should imagine that as Ahmed said, "The car was idle for about 15 minutes with AC turned ON," the engine would have got hot enough anyway.

If it was burning oil it would normally show as blue smoke with a distinctive smell. You would also notice it when accelerating after the car had been on overrun, for example when accelerating after a long coast down a hill with your foot off the accelerator.

I have only managed to catch the immediate aftermath of a GPF Regeneration once after a run. It was similar to a Diesel Regeneration, you could sense the excess heat as soon as the car door was opened. I never noticed any smoke, but I was not looking for any.

It is worth remembering that water is a by-product of burning any Hydrocarbon fuel. 

Thank you all for these valuable replies I really appreciate this 🙂 

There are some points that need clarification here : My car is stage V European emissions which I think it doesn't have a GPF.

The car was hot enough when this happened just like @Bobr said, I was driving for about 15 minutes (outside air temperature 36 Celsius ) and then when I came to a stop I was idle with AC ON for another 15 minutes before this happen, so I don't think its a condensation.

and also about the shaking that happened at the same time ( a single shack ) it should be related to the smoke somehow !!

A friend of mine here in Egypt who has mk8 fiesta told me that he also had experienced similar issue before, he was driving really fast , about 105 mph, then he came to a stop and he let the car idle and went away to buy something from the supermarket, and when he got back he noticed that white smoke that lasted a minute and then every thing is fine again, for him also no lights no errors no messages , fluid levels ok , car drives great !!!

Could it be a characteristic for this car ? what is happening ? 😄 

Maybe the EVAP Charcoal Cannister needed to be quickly purged because of the extreme heat conditions instead of being gradually feed into the engine when it was running.

The only way you will know for sure is to live monitor as many parameters as possible while replicating the same conditions.

As you said there were no warnings or fault codes so if it was likely to cause any damage I would have thought one would have popped up.

The engine was hot and in the process of cooling down while running on idle. There may be some localized heat in the engine that caused a cylinder to misfire and throw some white smoke out. The sudden shake could be a misfire. Did some coolant seap into the cylinder and cause this due to localized overheating. If it happens again it might be worth checking the torque settings on the cylinder head bolts. The head gasket might be ok but localized heating might allow some coolant to get through to the cylinder if the head bolts have loosened. The car being stationary means less cooling from airflow, and the ac on might lower the cooling effect on the engine.

If the car is driven hard and the left for 15 mins withe the ac on, the problem should easily repeat if the above is the cause. If it does not repeat then the above is wrong and that's good news.

Bear in mind it was idling in a temperature of 36 degrees.

That charcoal canister valve is very interesting actually , tonight I tried to reproduce the issue , drove for about 20 minutes, then let it idle for about 25 minutes, waiting for the issue to happen again, but It didn’t, observing the tail pipe i noticed condensation, seems to be normal condensation rather than coolant, since there was no smoke or smell at all, outside air temperature this time was 28 celsius.

Here is a photo of the tail pipe

https://ibb.co/9ygtJZC 

could it be something in the petrol that was already burnt and there is nothing else ? Or could it be the pcv system for example ? 
I really appreciate this help from all of you guys, you are my family here ❤️❤️

I think you'll have to wait a while Ahmed.   The filter has to be full of particulate before it can happen again.