Exhaust Smoke after catless

[nikitosik1989]

Does anyone experience whitish smoke when idling after going complete catless and when its 15-25 degrees Celsius. I am not sure its turbo seals or what. Car seems fine and has power. No Codes. Just a smell of fuel because of catless. Just had Spark Plugs replaced and the secondary coolant for the turbos added since it was low and made the car very low on power. (Felt Like driving 6 cylinder) Power is now back to normal

Here is the link to the video: https://www.youtube.com/shorts/06EpemXFfRQ

Thank you

2017 X6M F86

[Trion_f85]

The importance of exhaust gases is that it gives you an idea of whats happening in the combustion chamber, in the sense that

White smoke would generally signify water, coolant or water vapour.
Blueish white smoke signifies oil
Black smoke indicates rich air-fuel mixture
& so on

In your case if its white, this could be water vapors which normally burn off after a cold start but that should go away after the exhaust system warms up and there should be nothing to worry

But when car is up to temp. and everything is working the way it should, there should be no visible emissions coming from the exhaust whether stock or catless especially at idle speeds

The secondary coolant reservoir that was recently filled up is for the charge air coolers (Intercoolers) not turbos.

You should continue to monitor levels of that secondary coolant reservoir because levels hardly go low, if it goes below max again then that should point out to where the smoke is originating from.
Secondly if you can open your oil fill cover and check if theres some visible brownish foam lying in the tube.

[nikitosik1989]

Originally Posted by Trion_f85

The importance of exhaust gases is that it gives you an idea of whats happening in the combustion chamber, in the sense that

White smoke would generally signify water, coolant or water vapour.
Blueish white smoke signifies oil
Black smoke indicates rich air-fuel mixture
& so on

In your case if its white, this could be water vapors which normally burn off after a cold start but that should go away after the exhaust system warms up and there should be nothing to worry

But when car is up to temp. and everything is working the way it should, there should be no visible emissions coming from the exhaust whether stock or catless especially at idle speeds

The secondary coolant reservoir that was recently filled up is for the charge air coolers (Intercoolers) not turbos.

You should continue to monitor levels of that secondary coolant reservoir because levels hardly go low, if it goes below max again then that should point out to where the smoke is originating from.
Secondly if you can open your oil fill cover and check if theres some visible brownish foam lying in the tube.

Thank you. I am going to BMW tomorrow to change the HVAC Blower. I will mention to them about the intercooler coolant levels. Its strange because no codes and no check engine light is present. Car is up the the temperature and warm when its smoking during Idle. When I drive, i do not see it behind me or when I stop at the red light. Only when Idle it seems.

[Trion_f85]

Great, let us know what they say as to the cause of the smoke

[nikitosik1989]

Originally Posted by nikitosik1989

Thank you. I am going to BMW tomorrow to change the HVAC Blower. I will mention to them about the intercooler coolant levels. Its strange because no codes and no check engine light is present. Car is up the the temperature and warm when its smoking during Idle. When I drive, i do not see it behind me or when I stop at the red light. Only when Idle it seems.

I spoke with the BMW foreman and he said that he will check the secondary coolant as it was bone dry when I had the power loss. He will also check the turbos, the cold side of it. The hot side is you need to take the whole car apart and i do not want to go that far. Its definitely not turbo line blockage since it would smoke like locomotive. Could be turbo seals letting a bit of oil but my smoke is white not blue. Catless cars do smoke but how much is too much, that's the question. I will keep this post updated...

[Trion_f85]

How is your oil consumption? How regularly do you top up?

[nikitosik1989]

Originally Posted by Trion_f85

How is your oil consumption? How regularly do you top up?

Oil consumption is good. No Oil leaks. My car got diagnosed and No cracks or leaks to speak off. BMW checked the turbos there is a cold and hot side of it. To check the cold is easier and everything was good. i did not do the hot side since it would need to take the whole care apart and its too drastic. If there was a problem on the hot side of the turbo than I would see it on the cold side as well which was not the case. So what was concluded, is that white smoke just unburned fuel and not a coolant or oil leak. Possible slight turbo seal leakage but nothing major and just a symptom of going catless. That makes sense since i went to smell that smoke from exhaust and it did not smell like burnt oil or sweet like coolant. My secondary coolant system was bone dry but there was no cracks or any leakage which is weird. They also said that more smoke than usual could be because of a tune + going catless.

[Trion_f85]

Great u checked it out and no leaks. Idk but now smoke of any kind just rings alarm bells in my head : )
I run catless too btw, but do you have more smoke when you rev to higher speeds?

[nikitosik1989]

I am with you man. Any smoke is like a nail in my heart. Not Really no smoke that I can see from my rear mirrors. And also when I had smoke, it was cooler temperatures. Around 15 Celsius. Its going to be hot again in a few days, and I will see if its smoking during hot temperatures. Do you smoke at all as well, in any conditions or no smoke at all? I also have an M5 competition and it does not smoke at all and its fully catless. Probably from different design than the X6M.

[Trion_f85]

Currenly I do not have any smoke in all conditions with my catless dp & stage 1 tune. But i used to have some smoke at idle which was due to bad valve stem seals coupled with high oil consumption, the engine failed and i had to rebuild it but since then no smoke now.


The M5 and X5M/X6M have basically same engines S63, with the exception of oil pump, the M5 oil pump is fixed to upper oil pan while ours (X5M/X6M) is fixed on the engine block just like in the N63.

[nikitosik1989]

Originally Posted by Trion_f85

Currenly I do not have any smoke in all conditions with my catless dp & stage 1 tune. But i used to have some smoke at idle which was due to bad valve stem seals coupled with high oil consumption, the engine failed and i had to rebuild it but since then no smoke now.


The M5 and X5M/X6M have basically same engines S63, with the exception of oil pump, the M5 oil pump is fixed to upper oil pan while ours (X5M/X6M) is fixed on the engine block just like in the N63.

Jesus! engine failed How did it fail and how did you find out it was valve stem seals? I hope its not my case. Was your smoke at idle like mine in the video or more blueish?

[Trion_f85]

As you mentioned your oil consumption is normal, so hopefully nothing to worry, but i guess just need to make sure its unburnt fuel, you can show your tuner since this all started after the tune+catless

This was my case
https://f15.bimmerpost.com/forums/sh....php?t=2039065

[nikitosik1989]

Originally Posted by Trion_f85

As you mentioned your oil consumption is normal, so hopefully nothing to worry, but i guess just need to make sure its unburnt fuel, you can show your tuner since this all started after the tune+catless

This was my case
https://f15.bimmerpost.com/forums/sh....php?t=2039065

I will ask the bmw service techs to check for the valve stem seals if that is possible. Thanks for the help

[Trion_f85]

Its not an easy task but completely worth it your car is above 60k miles

[nikitosik1989]

Originally Posted by Trion_f85

Its not an easy task but completely worth it your car is above 60k miles

Agreed. Will see what they can do for me.