I'm owner of an Astra G estate. Motor Z16XE with BRC LPG system. This motor has over 100.000 miles. From the first day I used oil GM 5w30LL.
This motor has oil consumption from the first day. Now, when driving in city for only few kilometers (cold engine), consumption is high maybe even 1 liter / 1000km. The same is happening when driving on highways with over 3500 rpm's.
On the other hand if long distance drives has been made, and driving on 2500-3500 rpm's, oil consumption is ~0.1 liter / 1000km (maybe even less, because it is difficulty to drive always under 3500rpm).
There is no blue smoke on exhaust.
1. How come that oil consumption can vary so much?
2. I think to pass on Mobil Super3000 5w40 instead of GM 5w30LL. What are the experiences with this oil? What do you think about it? (now changing interval is ~10.000miles)