Smoking problem: Fixed

[stiubhartach]

Good post in #146. I agree with him and disagree with the follow up posters who claim to be BMW techs. I've known some terrible techs who were just glorified parts changers and didn't understand systems at all. Valve stem seals do fail, but CCV vacuum leaks are more common and far cheaper to fix. Remember as you diagnose ,that residual oil in the manifold and hoses will take a while to clean out.

Don't drive the car with a plugged CCV system. The crank case needs vented to the outside air to allow blowby to escape. The intake manifold hose port can be plugged indefinitely.

I fixed an old Alfa Spider I owned by putting a catch can in the equivalent vent line. I just manually drained it once in a while.

Good hunting!

[X5only]

Originally Posted by stiubhartach

Good post in #146. I agree with him and disagree with the follow up posters who claim to be BMW techs. I've known some terrible techs who were just glorified parts changers and didn't understand systems at all. Valve stem seals do fail, but CCV vacuum leaks are more common and far cheaper to fix. Remember as you diagnose ,that residual oil in the manifold and hoses will take a while to clean out.

Don't drive the car with a plugged CCV system. The crank case needs vented to the outside air to allow blowby to escape. The intake manifold hose port can be plugged indefinitely.

I fixed an old Alfa Spider I owned by putting a catch can in the equivalent vent line. I just manually drained it once in a while.

Good hunting!

To clarify, which ports do you mean can be plugged during diagnosis - red arrow or green arrow?

[stiubhartach]

Red arrows must be plugged or you get a vacuum leak which messes up the mixture. Green arrows need to be open, or vented to allow pressure that escapes by the rings into the crankcase to escape. Normally it gets sucked into the intake ( red arrows) and burned in the cylinders.

[fishhouse4]

Digging up an old thread here but just wanted to share my experience for others:

New to me 06 4.8is with 77k was producing white smoke after extended idle (~ 5 min or so). Of course I assumed it was the dreaded valve stem seals.

Anyways, after reading this thread I pulled the engine covers and investigated my CCV system. Found that the diaphragm on the right side had a tear and the breather hose on the left side cracked open. The PO (or their mechanic) choose to repair both with Duct tape!

Ordered new hoses and 2 CCV valves for both banks and cleaned inside the housings. Reinstalled everything and my smoke is gone!!! I expect oil consumption to improve (although I need to address small seep at top of upper time chain cover next).

Many thanks for this post! $60 in DIY replacement parts sure beats a valve stem job!!

[stiubhartach]

Congratulations on your victory over poor maintenance! Now we have proof that duct tape isn’t suitable for CCV systems. And congratulations on your new 4.8is. You’ll love it!

[X5M-ISH]

This thread (and the other linked thread to McDonaldD’s) compelled me to register and post. As others have stated, by virtue of the power of observation and a bit of mechanical basics, one can conclude that valve stem seals are not the likely culprate to the ‘idling smoke puff of shame’. Whether you drive a BMW or an Acura or Ferrari, vacuum leaks are the devil. This does not mean that valve stem seals don’t fail, it’s just not very common. Not as common as the internet would scare someone to believe and if true would be a huge failure on BMW’s part.

I picked up a 2006 4.8is last week knowing that their was smoking after prolonged idling. However, with how well the engine pulls like a freight train (and concluding a 2,000 mile road trip from picking it up at its place for sale) I am not convinced at all that the valve stem seals are bad. Coming across this thread after five days of searching different key words and reading all the subsequent linked-threads further solidifies vacuum/oil leaks that my IS is currently experiencing. Today being the first day I have had time to take a look around the N62, I have high confidence this is the case.

Summarizing my observations:
*passenger side valve cover noise dampener has oil around the knock outs for the dipstick and CPS.
*pulling off all noise dampening covers reveal both camp position sensors are weaping oil.
*the sensor on the pass-side valve cover in front of the CPS is weaping oil
*the oil filler cap is weaping oil.
*the oil dipstick is not nesting as tight as it should be. Generally on a new motor there is a bit of a ‘pop’ noise when pulling out the dipstick.
*CCV are in good shape, however there looks to be a misalignment issue on both valve covers (not sure if this is normal). Meaning the black plastic hole does not rest equally centered/alligned to the hole below it on the heads. These two respective holes are off by about 3 mm.
*passenger side vacuum hose valve-cover-to-intake-manifold is gummed up with brown crud throughout.
*driver side vacuum hose valve-cover-to-intake-manifold is gummed up with brown crud on the intake port side.
*the bunge located above the throttle body is restricted with brown crud.
*inside of intake manifold shows signs of oil contamination. While I can still see some of the green coating, oil is in there.
*PO had the alternator replaced. I am unable to verify whether the gasket was replaced during reinstallation as discussed in the McDonaldD’s thread. This can also be another point of contention for vacuum leaks.

*Oil consumption is low and under the threshold outlined by the BMW bulletin.
*Gas mileage is around 23-24 highway and 18 city.
*Engine purrs like a kitten at idle and through out rpm range.
*Engine pulls and pulls when the gas pedal is into it.
*no weaping anywhere else around or under the engine.

I like to weigh time involved vs repair price. I’ll be starting with the cheapest solutions first basically replacing every gasket, o ring and hose in and around the vavle covers. Thanks to the OP and McDonaldD for their insighful and detailed threads. Very much appreciated.

[X5only]

Originally Posted by X5M-ISH

This thread (and the other linked thread to McDonaldD’s) compelled me to register and post. As others have stated, by virtue of the power of observation and a bit of mechanical basics, one can conclude that valve stem seals are not the likely culprate to the ‘idling smoke puff of shame’. Whether you drive a BMW or an Acura or Ferrari, vacuum leaks are the devil. This does not mean that valve stem seals don’t fail, it’s just not very common. Not as common as the internet would scare someone to believe and if true would be a huge failure on BMW’s part.

I picked up a 2006 4.8is last week knowing that their was smoking after prolonged idling. However, with how well the engine pulls like a freight train (and concluding a 2,000 mile road trip from picking it up at its place for sale) I am not convinced at all that the valve stem seals are bad. Coming across this thread after five days of searching different key words and reading all the subsequent linked-threads further solidifies vacuum/oil leaks that my IS is currently experiencing. Today being the first day I have had time to take a look around the N62, I have high confidence this is the case.

Summarizing my observations:
*passenger side valve cover noise dampener has oil around the knock outs for the dipstick and CPS.
*pulling off all noise dampening covers reveal both camp position sensors are weaping oil.
*the sensor on the pass-side valve cover in front of the CPS is weaping oil
*the oil filler cap is weaping oil.
*the oil dipstick is not nesting as tight as it should be. Generally on a new motor there is a bit of a ‘pop’ noise when pulling out the dipstick.
*CCV are in good shape, however there looks to be a misalignment issue on both valve covers (not sure if this is normal). Meaning the black plastic hole does not rest equally centered/alligned to the hole below it on the heads. These two respective holes are off by about 3 mm.
*passenger side vacuum hose valve-cover-to-intake-manifold is gummed up with brown crud throughout.
*driver side vacuum hose valve-cover-to-intake-manifold is gummed up with brown crud on the intake port side.
*the bunge located above the throttle body is restricted with brown crud.
*inside of intake manifold shows signs of oil contamination. While I can still see some of the green coating, oil is in there.
*PO had the alternator replaced. I am unable to verify whether the gasket was replaced during reinstallation as discussed in the McDonaldD’s thread. This can also be another point of contention for vacuum leaks.

*Oil consumption is low and under the threshold outlined by the BMW bulletin.
*Gas mileage is around 23-24 highway and 18 city.
*Engine purrs like a kitten at idle and through out rpm range.
*Engine pulls and pulls when the gas pedal is into it.
*no weaping anywhere else around or under the engine.

I like to weigh time involved vs repair price. I’ll be starting with the cheapest solutions first basically replacing every gasket, o ring and hose in and around the vavle covers. Thanks to the OP and McDonaldD for their insighful and detailed threads. Very much appreciated.

Been there done all that - twice. I replaced every conceivable seal and gasket, including the oil dipstick seals and oil fill cap seal....everything (valve cover and upper timing case gaskets, vacuum pump seals, etc). What a waste of time and money - the vehicle still smoked like hell. But this is just my case. Yours could be totally different. Nonetheless, by replacing the valve cover gaskets, you've done nearly 80% of the work involved in valve stem seals replacement! So why not just go the extra step to replace them, whether they're the culprit or not. You see, I was in the same boat and I really wanted to avoid tackling the valve stem seals because I was very fearful of the work involved and tools. I don't have a reliable air-compressor and was concerned that family and neighbors would complain if I got a larger one. However, later I learned that an air-compressor is not required (a bungee code is an alternate) and, having watched numerous videos, the task of replacing the valve stem seals is not hard - just time consuming. And I found a cheaper tool (about $370) as an alternative to the AGA tool.

[stiubhartach]

Originally Posted by X5M-ISH

This thread (and the other linked thread to McDonaldD’s) compelled me to register and post.

*passenger side vacuum hose valve-cover-to-intake-manifold is gummed up with brown crud throughout.
*driver side vacuum hose valve-cover-to-intake-manifold is gummed up with brown crud on the intake port side.
*the bunge located above the throttle body is restricted with brown crud.
*inside of intake manifold shows signs of oil contamination. While I can still see some of the green coating, oil is in there.

Welcome to the Xoutpost community! And congratulations on purchasing an excellent piece of engineering.

Notes on your findings.

1. Oil in the throttle body and intake manifold indicates that it’s sucking oil out of the engine. There no other route for oil to enter the intake manifold. And the only exit route is into the cylinder and out the tail pipe as smoke.

2. External oil leaks are messy, but don’t harm the engine. As long as you keep the oil level up. So, if you’re looking to minimize cost, you can wait. Just park over cardboard.

[Emory39]

The X5 had been burning some oil and a small puff of smoke after extended Idle. I have replaced the CCV last November I thought cool that's it. But no still burning oil, so today I decided to look into it and ended up finding this threat.


*I have no visible oil leak.
* CCV system is clean of gunk
* there is oil residue in the hoses and the intake


Heres what I think is where it gets weird, or it is ok.
I did a vacuum test at various spots.


*intake manifold 0 vacuum
*small hose at intake hose 0 vacuum

*dip stick 0 vacuum
*vacuum pump 60 vacuum




the gauge did not register any vacuum on those places, but there was maybe 0.5 in vacuum.
Can someone with a vacuum gauge test this spots for vacuum and report back? Or give me another point of views that I might be missing.

[stiubhartach]

The VANOS engine controls rpm by adjusting the valve timing rather than throttle position (air flow). The throttle plate opens fully while the engine is running. This means that there’s negligible vacuum at idle. That’s the main weakness of the CCV system.

Here’s more info:

https://www.bimmerfest.com/forums/sh...d.php?t=911135