quick (maybe dumb?) question...i have been using pennzoil for my last 2 oil changes (self done). 5w30 both times. so now i have about 2L leftover (about 1L leftover each time).can i buy another brand (non-synthetic) at 5w30 and mix with the 2L pennzoil?thanks.
I have signatures turned off so I'm not even sure what mine says in this space!