[Piet]

Dorgohodez, i hope you can read english.
Synthetic oil for a Niva is not so good, because it is very thin. The engine of the Niva is based on a old model with big margins. Therefore the engine wil consume more oil than with mineral oil or half synthetic. What you can do, is change again the oil, and first try mineral oil of a good brand.

My engine is already 18 years old, and have driven 170.000 km, and is consuming 0,5 to 1 ltr max on 5000 km.