996 oil smoke

[swiftus]

Question about what is 'normal' on a 996 3.6 and oil smoke at start up.
My 3.6 had the normal 996 engine work done 700 miles ago. When starting from cold I get a puff of blue smoke from the exhaust (more one side then the other). Bore scope test has just been done and there are no signs of any damage.
I am finding conflicting information about if this is OK to smoke at cold start or not. Is this 'normal', or a sign of a problem with the rebuild?
Neither my 3.2 or my 993 ever smoked or used any oil.
Thanks!

 

[rapid1]

I have also had this problem especially when the engine has been stopped and then restarted after a hard drive. But my car does not use any oil so I am not too concerned about the occasional smoking. However since I fitted an X50 spec sump, the problem has all but disappeared ....the standard sump has plastic and thin rubber baffles which deteriorate with age. The Air / Oil separator can also be the cause of smoking but it looks like a b...... of a job to replace, so I haven't done it !

 

[swiftus]

Ok thank you.
It has also had a new air/oil separator, so that shouldn't be the issue. So issues with the sump can cause smoking? I'll look at that.
I am trying to figure out if I should be taking on the dealer who did the work about this? If 996's do generally blow blue smoke at start up that wouldn't be fair. It seems an odd thing to accept from a rebuilt engine?

 

[nicholasfinlay]

I certainly hope it is normal - I get alot of smoke (more grey than blue) when the car's not been used for a while. Again, it's much more on one side.
Regards
Nicholas

 

[C2dweller]

I think you were lucky with your previous 993 and 3.2. Most of the flat-6 engines we see will smoke occasionally from cold. My own 964 is no different.

The fact you report it from one bank more than the other would suggest it's not something common to all cylinders, like an AOS.

When they performed the borescope, did they take pictures? I ask because we always see some degree of wear on an original (none rebuilt) engine.

if oil consumption is low, I would be tempted to put it to the back of you mind and just enjoy the car.

KR Lee

 

[swiftus]

Interesting stuff, thank you all.
I don't have the scope results, but the scope wasn't done by the garage that did the rebuild, so I expect it to be accurate (honest!), as they weren't checking their own work (and liability to fix).
I get dark grey smoke after the blue smoke, then white, so that seems ok to me (then again my others just went straight to white).
I don't know what the oil consumption is yet, I have only driven it for 50 miles! I do think that the oil was overfilled at the rebuild, but the oil was changed last week before the garage actually checked the level, so they couldn't confirm.
It will be interesting to see if anyone has the view that it is not okay to blow smoke at start?
Thank you,

 

[Gordon Attar]

Why the rebuild may help answer and why the later bores cope it takes more than 800 miles to show up.
Very common for all 911's to smoke and tap when cold on start up, the grey smoke is of concern.
Overfilling will exasperate which maybe the cause of the grey smoke

You need to do a good hundred miles after the last check and refill. If it's still going on then I would go back to the rebuilds.

 

[swiftus]

[FONT=calibri"]Subsequent to your helpful thoughts I thought I would update this post.
[FONT=calibri"]I decided that the issue needed attending to as after being left for 3 days the blue smoke was considerably worse compared to being left for 1 day, and both banks were smoking. The smoke didn’t clear immediately either.
[FONT=calibri"]So, the car went away and had new valve guides and that seems to have fixed it. I haven’t yet tried leaving it for 3 days without running the engine, I’ll do that by the end of this week.
[FONT=calibri"]The oil level now seems to be correct.
[FONT=calibri"]I haven’t managed to find out why the engine was rebuilt, but it had pistons and IMS. So I am assuming that they decided the head side of it was ok, which it wasn’t.
[FONT=calibri"]Fingers crossed!