White smoke, no leaks !

[hitpoint]

Hey people!


I have a BMW e92 325i auto (y2008, engine N53) with arond 140k km.
So, the problem started somewhere in September 2017. It began with white smoke when the car is idle (from its exhaust), 10 minutes after start, waiting on trafiklight etc. It wasnt so thick, but I could see it from my side mirror. In time I noticed (also on my side mirror) that I could see the smoke while I was driving too. There was more and more white smoke every day. Today, the smoke is still here, even more visiable and thicker maybe because it's pretty cold outside (I live in Sweden, -5C today). I also noticed that when I drive and I relase the gas pedal, I can't see the smoke on the mirror. So, maybe, much less smoke when releasing the gas pedal..
I ran a diagnostics at a proper mech and it showed nothing. NOTHING! The engine works perfectly, no sound, no oil leaks, no coolant leaks. The mech didn't know what to do, so we tried with an Acute Injector Cleaner. No luck at all of course. Before I go and pay just 100 euro for another diagnostics and a lot more for a repair (if there is a big problem with the engine) at a BMW specialised service, do you have any thoughts on this?

Thank you!

Deni

 

[Coisman]

Possible it's the valve stem seals leaking oil into the combustion chamber :dunno:

 

[Peter@AEW]

Possible it's the valve stem seals leaking oil into the combustion chamber :dunno:

As has been already proposed.

I would do an engine compression test to verify that cylinder pressures are good.

White smoke under acceleration is typically a sign of cylinder head component failure and white smoke under deceleration is a sign of piston/piston ring failure.

 

[hitpoint]

Well that can't be good.. I don't feel a loss of power and the temp never goes over one half. Rarely reaches half. And there ware no errors on that computer testing
But, if it is the problem that you guys suggested, is it something complicated and expensive? Is it better if I pay a little extra and visit a certified BMW mech or? Is this a common problem with this engine?

 

[Peter@AEW]

Well that can't be good.. I don't feel a loss of power and the temp never goes over one half. Rarely reaches half. And there ware no errors on that computer testing
But, if it is the problem that you guys suggested, is it something complicated and expensive? Is it better if I pay a little extra and visit a certified BMW mech or? Is this a common problem with this engine?

You could perform a compression test yourself if you have the tools.
It really is not a procedure which requires the services of a rocket scientist.

Expensive is a relative term so I guess on a scale of 0 to 10 a cylinder head overhaul would rank as a 5 and an engine overhaul as a 10.

Ask your mechanic to do the compression test first and post the results here.

The test should be done with the engine hot and it should be performed twice.

The first test you record the numbers
The second test you pour a small amount of engine oil in the cylinders maybe 4/5 drops or so and you record the numbers.

If there is no variance between the readings with and without oil it is a cylinder head issue.
If the second set of numbers is improved in comparison to the first it is a piston/piston ring issue.

 

[hitpoint]

Well that can't be good.. I don't feel a loss of power and the temp never goes over one half. Rarely reaches half. And there ware no errors on that computer testing
But, if it is the problem that you guys suggested, is it something complicated and expensive? Is it better if I pay a little extra and visit a certified BMW mech or? Is this a common problem with this engine?

You could perform a compression test yourself if you have the tools.
It really is not a procedure which requires the services of a rocket scientist.

Expensive is a relative term so I guess on a scale of 0 to 10 a cylinder head overhaul would rank as a 5 and an engine overhaul as a 10.

Ask your mechanic to do the compression test first and post the results here.

The test should be done with the engine hot and it should be performed twice.

The first test you record the numbers
The second test you pour a small amount of engine oil in the cylinders maybe 4/5 drops or so and you record the numbers.

If there is no variance between the readings with and without oil it is a cylinder head issue.
If the second set of numbers is improved in comparison to the first it is a piston/piston ring issue.

I don't know if I have the tools. What should I have to do this test properly? If not, I have to book the test at BMWs service and then post it back here... I just bought the car, in August/September. Gave all my cash damn it
Thank you for your help and suggestions! As soon I have the results I will post back here.

---

Is this info any usefull: When the engine is hot and running, I have twice removed the oil cap and felt the compression / vacuum. While the cap was removed, the sound of the engine changed a bit.