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Strange Grey Smoke??


New member
30 Aug 2003
Took delivery of the new C2 a few weeks ago and have driven 300 mls so far with great pleasure. However, whenever the car has not been driven for more than 36 hours there is a strange thing happening on cold start. The moment the engine starts running there is a pretty large cloud of almost totally grey smoke to be seen from the left hand side bank exhaust only! All goes away after a couple of seconds and nothing comes out of the opposite cylinder bank exhaust!!??

No matter how many times the engine is switched off and started afterwards - even after almost a day - it is all fine and no more smoke or anything is to be seen.

Has anyone seen or experienced this? Well, whatever it is, it must be coming either out of the cylinders or the left hand cylinder bank exhaust system. Also, why not from both sides? I am full acquainted with the dry sump oil system as well as the scavenging tank, etc., but unless it is a large amount of excessive fuel used for totally cold start (again, why only on one half of the engine?) it can only be some oil (or what else?) left in those 3 cylinders that shoots out when ignited and burnt.

Althought I am no panicking, I think I will raise it wih my dealer after weekend, but wonder if any input may come from other members in the meantime. By the way, the oil level is perfect and the car performs fine in every respect.

many thanks


Migration info. Legacy thread was 7691
Post an question on the JZ Mactech forum I think you would get an unbiased opinion there. I wouldn't trust a dealer.

Migration info. Legacy thread was 7692
I had this on my first 993, if left for more than a day or so it would chuck out clouds of smoke on start-up, I never did anything about it and put it down to the dry sump etc. However, my new 993 doesn't do it at all which is odd considering it's done many more miles and is much older...

Migration info. Legacy thread was 7698
Build up of carbon and so on in the engine if left sitting, the smoke is it being burnt off, its common. Solution: drive it more!

(Can see why my mum calls me an anorak)

Migration info. Legacy thread was 7703
i must say noony, i am very impressed with your range of knowledge for such a young nipper. keep up the good work!

Migration info. Legacy thread was 7704
Carbon doesn't build up whilst the engine is left sitting, and if it was blowing out smoke out of one bank of cylinders, how come there is no 'carbon' in the other . I don't think there's a chance the smoke issue is carbon related on this engine, it's much more likely to be a cold start issue (I don't know what they use on a 996) or a drain pipe bleeding into one bank of cylinders or the exhaust, possibly designed to burn off on start up. The advice about driving it more and hard is correct though.

Migration info. Legacy thread was 7705
Yes sorry I'm not sure what it was that burns off when left to sit then started again, but I heard this is common. Who buys a brand new porsche to not drive it anyway?

Migration info. Legacy thread was 7706
It could be just condensation that because of the exhaust arrangement on a 996 exits from one exhaust only. Worst poss' is a slight head gasket leak on that bank of cylinders.

Migration info. Legacy thread was 7707

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