Black smoke from exhaust on startup

[Guest]

I have a mate in deepest Cornwall with an 03 Boxter S that sometimes emits lots of black smoke from the exhaust when it starts - usually mainly cold but occasionally warm starts. It's been into OPC Exeter twice who have replaced the oil separator - other repairs carried out relating to oil loss from rear mail oil seal, NS differential seal and oil fill neck
The explanation from the OPC is the slight gap in piston rings causes minimal amount of oil to seep past which is burnt at start up. Only happens when gap is in a certain position. Porsche technical confirmed this is a characteristic and not a defect. Sounds plausible but it's only been happening for 6 months, not from new.
Any ideas?

Chrissie
996 C4 Tip Arctic Silver

 

[JCB..]

ORIGINAL: chrissie996

I have a mate in deepest Cornwall with an 03 Boxter S that sometimes emits lots of black smoke from the exhaust when it starts - usually mainly cold but occasionally warm starts. It's been into OPC Exeter twice who have replaced the oil separator - other repairs carried out relating to oil loss from rear mail oil seal, NS differential seal and oil fill neck
The explanation from the OPC is the slight gap in piston rings causes minimal amount of oil to seep past which is burnt at start up. Only happens when gap is in a certain position. Porsche technical confirmed this is a characteristic and not a defect. Sounds plausible but it's only been happening for 6 months, not from new.
Any ideas?

Chrissie
996 C4 Tip Arctic Silver

White smoke is normal.

Black smoke - That's what diesels do isn't it?

 

[Geoff_Fields]

Surely black smoke would indicate over fueling so pointing to the injection system. Bluish white smoke is quite common and OPC diagnosis would then be more accurate.