Smoking on Deceleration

[MoB123]

Hi guys,
Apologies i am new at this.
I have a 335i e90 m sport 2009 with 190000km. I have the car for a year and have done appx. 6000km.
In the last few weeks the car has started smoking on deceleration.

It has been to a mechanic who suggests that the engine rings and valve stem seal need replacement.

He has stripped the downpipes and confirmed that there is no oil coming from the turbos. (As per the mechanic)

The PCV valave has been changed with one from renzzport a metal one.

I am completely lost currently and dont have a way forward.

Any suggestions.

 

[Yuben]

Thread/1st post split from other thread with same title and similar problem

 

[SubLoaded]

Valve stem seals smoke on acceleration. Is that the same mechanic that told you that the turbo is fine?
Not implying anything but perhaps get a second opinion.

Are both exhausts smoking or just one side?

Turbo seals is my bet...

 

[ver328i]

is it that annoying blue cloud that passes u when you stop at the robots? smells of oil? and only really there when the car is hot? then its turbo seals friend...more noticeable with decatted downpipes

do a compression test to see if rings are required...valve stems seals will smoke white so just be sure youve rulled out everything before having this mech rip your engine apart.

 

[Kish2604]

Hi guys,
Apologies i am new at this.
I have a 335i e90 m sport 2009 with 190000km. I have the car for a year and have done appx. 6000km.
In the last few weeks the car has started smoking on deceleration.

It has been to a mechanic who suggests that the engine rings and valve stem seal need replacement.

He has stripped the downpipes and confirmed that there is no oil coming from the turbos. (As per the mechanic)

The PCV valave has been changed with one from renzzport a metal one.

I am completely lost currently and dont have a way forward.

Any suggestions.

Any idea when the turbos were last recon/changed? the stock turbos have a weak thrust washer which as they get older and accelerate wear on the seals. that is why when you lift of the accelerator pedal it allows minor amounts of oil to bypass and creates all that blue smoke when coming to a stop. It typically is the rear turbo that fails.

 

[MoB123]

Thanks guy's.

Smoke does appear from both exhausts.
And yes its the same mechanic. He also opened the oil cap with the engine running. There is alittle smoke /fumes that come out. He said that is a sign of rings.

Will definately do a compression test first.

Will report with findings

Tnx alot for the advice

 

[gavsadler]

So my 2c, from what I know of previously:

Smoke when accelerating points to worn piston rings,

Smoke when coasting (no load on engine / overrun) points to worn valve stem seals.

As others have mentioned, turbos are a possibility, but if the downpipes are off and no sign of leaks, then the problem lies elsewhere.

 

[Kish2604]

Thanks guy's.

Smoke does appear from both exhausts.
And yes its the same mechanic. He also opened the oil cap with the engine running. There is alittle smoke /fumes that come out. He said that is a sign of rings.

Will definately do a compression test first.

Will report with findings

Tnx alot for the advice

i just want to say... find another mechanic, preferably someone with the knowledge of a modern day BMW motor.

If your in GP get in touch with Afzil (search the forum for his details) or in Durban then The BM Workshop.