[repete]

Hi all,

Yesterday, I started my 2006 330i up after sitting overnight in the cold, and noticed a nice big blue puff of smoke that came out of the exhaust, then cleared up shortly thereafter.

When I was driving to work this morning, no blue smoke on startup. Seemed fine, made it almost all the way when I noticed a much bigger cloud of smoke coming from the exhaust. Also seemed to be a bit down on power at this point.

So, here’s what I’ve got so far: A good few months ago, I had just finished replacing the head gasket, as I had experienced lots of cooling system problems in the past leading to overheating and eventually burning up of coolant. The head was fairly warped, had it machined, checked the block and it was okay. After reassembly everything did fine for a while. I did NOT replace valve seals when I was in there which now I am wondering if I should have.

There has been almost no oil consumption recently, until just now. I’ve gone almost 5k miles since my last change and only added maybe 1qt so far. I’m not sure how much it’s sucking down now, I’ll have to see what it’s doing once I’m off work.

The only things I can imagine it would be are:

• Valve seals - would explain smoke on startup then nothing, but makes less sense considering the second cloud of smoke when it was up to temp.
• CCV - I have replaced a couple of the tubes, but not the oil separator. Could one/multiple of these components fail in a way that could explain the smoke?
• Piston rings/damaged piston - possible, I have almost 215k miles now, but I would expect to see more consistent oil consumption.

I will see if it’s still smoking once I’m off work today, may/may not attempt to drive it home depending on how bad it is. I’m thinking I’ll pull the intake and see if the valves or intake are wet with oil, may also pull plugs and take a look in the cylinders with a borescope. I saw a couple threads regarding testing the diaphragm in the oil separator with light suction, I’ll definitely test that as well.

Any other theories or suggestions for diagnosis before I resort to drastic measures? Anyone else experienced this before?

In all honesty, I wouldn’t mind rebuilding or replacing this engine if it came down to it. I know it’s just an n52 but I’m a little crazy (and put too much effort into things that probably don’t deserve it), plus I already have most of the special tools for it.

Let me know what you guys think, I’d be happy to hear what tests I could do to try and narrow this down. Thanks!

[Saico]

Hi,

I think you are thinking correct, my line of action would be similar but with different sequence:
1. Replace CCV - most probable cause
2. If this doesnt help check compression or even better leakdown test
3. If compression/leakdown good look into vavle seals. But from my experience these do not fail suddenly

[repete]

Just a quick update, got off work and was able to drive home. There was a small cloud of smoke on startup, once the cats warmed up it seemed to go away.

While driving, there was not much smoke unless I went above about 2500 rpm, leading me to believe the CCV drain to the oilpan is plugged or the ball valve is stuck open, and the CCV valve stuck causing full vacuum to the return, sucking oil up from the oilpan. This thread proved very useful in explaining how these CCV’s can fail.

Originally Posted by Saico

1. Replace CCV - most probable cause
2. If this doesnt help check compression or even better leakdown test
3. If compression/leakdown good look into vavle seals. But from my experience these do not fail suddenly

Thank you for the input! I agree the valve seals are probably okay too, now that I’ve considered the CCV could be responsible. I will pull the intake off and get a look at things just to be sure, but you’re probably right, I haven’t replaced the CCV separator since I bought the car, only a couple of the hoses.

[repete]

Update: pulled off the intake, and yeah. I’m 99% sure it was the CCV causing the oil to get sucked up. Intake has probably half a quart of oil just chilling in there

It doesn’t seem the valves were unusually wet/oily near the stems, so I no longer suspect stem seals. One of my DISA flaps was broken as well, gonna get a replacement for that too.

Got the whole CCV kit ordered, as a note if you’re replacing yours, make sure you get the right kit! There are two, one is for models built before 10/2005 and the other is for after. Mine is an 06, build date 05/2005 so I got the earlier version. You can check build date with a VIN decoder or ISTA.

I will update once I install the new CCV parts, should solve this issue!

[TractionControlDelete]

Originally Posted by repete

Update: pulled off the intake, and yeah. I’m 99% sure it was the CCV causing the oil to get sucked up. Intake has probably half a quart of oil just chilling in there

It doesn’t seem the valves were unusually wet/oily near the stems, so I no longer suspect stem seals. One of my DISA flaps was broken as well, gonna get a replacement for that too.

Got the whole CCV kit ordered, as a note if you’re replacing yours, make sure you get the right kit! There are two, one is for models built before 10/2005 and the other is for after. Mine is an 06, build date 05/2005 so I got the earlier version. You can check build date with a VIN decoder or ISTA.

I will update once I install the new CCV parts, should solve this issue!

But before you do, be sure to check with BMW as they issued this letter that likely covers your car (below). May cost you nothing at all

[repete]

Originally Posted by TractionControlDelete

But before you do, be sure to check with BMW as they issued this letter that likely covers your car (below). May cost you nothing at all

Definitely, thanks for the info! Unfortunately with 215k miles (and 17 years old) my car isn’t eligible

[TractionControlDelete]

Originally Posted by repete

Definitely, thanks for the info! Unfortunately with 215k miles (and 17 years old) my car isn’t eligible

No no, read it again!! It says that your 15 year/150k mile warranty is extended for the purpose of the PCV repair.

It says “BMW is extending the warranty”