White/blue smoke appears sometimes on cold start. Afterwards everything clear. Car is KIA Shuma 1.5 2000y 160000km gasoline. Car has no oil consumption (no oil addition necessary between change intervals).
Same behavior started on my brothers KIA Shuma 1.5 1999y with 250000km (more worn out engine. Needs oil filling between intervals).
It is possible that time when these issues started coincided on both vehicles when same new oil was used.
Is it a valve seal? Could valve seal be ruined/hardened by bad oil?
Is it simply worn out engine (although I don't think so).