Just came across this vintage can of Shell X100 30/40 Motor oil ,while i looking for Rimula 20w50, what does this mean? does it act like a 30 when cold and like a 40 when hot?
https://swapmeet.net.au/product/Shell-X100-Oil-Tin-467
https://swapmeet.net.au/product/Shell-X100-Oil-Tin-467