Make sure to drain out the oil pan drain plug every once in a while to get the small shavings which should be stuck to the plug — it’s magnetic to hold on to them.
I think you mean privacy, not security, which there aren't really any claims about.
Google aims to provide security updates to all Android devices, but specifically targets their product lines (Nexus, Pixel, etc) and Android One devices as they have a little more control over the software.