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!