Blue Smoke on Startup - Occasionally

I did some searching, but admit to be lost in the acronyms.

A few times over past couple weeks I have noticed a huge cloud of blue smoke coming out exhaust on my '06 330 Ci. Each time this was at work, after the car sat approx 9 hours in cold weather. At home my car is in garage, no less than 50deg. My drive to work is 20 minutes. There is no smoke in morning, in garage. Again, the only 3 times I have seen this smoke is after setting outside in cold weather for approx. 9 hours.

After trying to research this, I found threads about some crankcase ventilation tubes needing cleaning. I removed oil fill, and saw yellow slime. Next I pulled the tube at top of valve cover. What I found there was gross, it appeared to be filled with yellow snot. I cleaned as best I could by snaking a piece of weedeater cord down into tube, pulling out, wiping clean, etc. many, many times. I could not see any way to disconnect the other end of tube, even after removing air cleaner.

Did I fix the problem by cleaning this tube, -or- will a long drive fix the issue, by heating up everything, and evaporating the sludge -or- do I need to replace some parts?

Ironically there is a thread I did not find in search, but happened to be currentlly active, it describes how to replace all the Crankcase Ventilation stuff - -> http://forum.e46fanatics.com/showthread.php?t=643639

This thread seems to address mainly leaking oil, and Codes (neither of which I have). Can faulty CCV/OS stuff cause a momentary puff of blue smoke out the exhaust?

Another thread showing how to replace a commonly cracked OS hose:
http://forum.e46fanatics.com/showthread.php?t=773551

I might just try to clean up some hoses etc. to see if problem goes away (unless someone has more definate answer)


Just to clarify, I have only seen the smoke occasionally at startup, not like valve seal issues of smoking after idling, or down-shifting to slow down, and then giving throttle.

Yes, that can cause all of that. It's time to replace it.

Originally Posted by BMWfever

I did some searching, but admit to be lost in the acronyms.

A few times over past couple weeks I have noticed a huge cloud of blue smoke coming out exhaust on my '06 330 Ci. Each time this was at work, after the car sat approx 9 hours in cold weather. At home my car is in garage, no less than 50deg. My drive to work is 20 minutes. There is no smoke in morning, in garage. Again, the only 3 times I have seen this smoke is after setting outside in cold weather for approx. 9 hours.

After trying to research this, I found threads about some crankcase ventilation tubes needing cleaning. I removed oil fill, and saw yellow slime. Next I pulled the tube at top of valve cover. What I found there was gross, it appeared to be filled with yellow snot. I cleaned as best I could by snaking a piece of weedeater cord down into tube, pulling out, wiping clean, etc. many, many times. I could not see any way to disconnect the other end of tube, even after removing air cleaner.

Did I fix the problem by cleaning this tube, -or- will a long drive fix the issue, by heating up everything, and evaporating the sludge -or- do I need to replace some parts?

i have exactly the same issue, some guy told me i'm burning oil and that i need to take the top part of the engine off and redo my heads? is this all bs? the car drives fine, the dipstick was dry so i did add some oil in there. no leaks, but the slime does exist. this is most likely the ccv?

Originally Posted by madunix

i have exactly the same issue, some guy told me i'm burning oil and that i need to take the top part of the engine off and redo my heads? is this all bs? the car drives fine, the dipstick was dry so i did add some oil in there. no leaks, but the slime does exist. this is most likely the ccv?

Your engine does not need work. Many owners don't drive their cars long enough - time and/or distance - for the engine to reach full operating temperature. As a result the CCV doesn't reach operating temperature and condensation results in sludge.

Blue smoke is related to oil being burned. I suspect your engine's ccv is sending small amounts of oil to the intake at start-up.

As I'm sure you are aware, these engines are complex, and have been designed and made to operate optimally at a narrow range of (engine) temperatures. I recommend that every BMW owner drive their car AT LEAST 20 miles at highway speeds on a weekly basis. This ensures that each car's engine reaches full operating temperature. The benefits:
- condensation is boiled off
- combustion by-products (i.e., gasoline detergents (e.g., Techron)) are boiled off

Oil seperator could be failing which causing smoking upon startup.