Landlord has a problem with my guest

My boyfriend swings by my place once a week during the day. He has a loud car. I’ve been told by my landlord that he has a loud car and needs to keep it down but obviously there’s no way we can control the volume of the car… but we’ve always been mindful about when he comes, and it’s always during the day

Anyway, yesterday he confronted my boyfriend outside while I was still inside my place and said that if he doesn’t make his car quieter he’d call the cops for noise disturbance and being an unwelcome guest on his property. He was literally screaming at my boyfriend. He has yet to address this conversation with me, as he’s probably under the impression I didn’t hear what happened because I was inside

I live in an ADU (California) so my landlord is always on the property

Bottom line, I’m scared to go home and I’m hoping to have some kind of legal defense for myself if he were to get hostile with me and threaten to evict me over this situation