Hello
Are both of the given sentences OK? Is there any change in meaning?
1- Roll down the car window, please.
2- Open the car window, please.
Is
roll up= close?
Tom
Hi Tom
Nowadays cars often have a nice set of buttons that open and close the windows electronically (“power windows”), so very technically speaking, that’s not really “rolling” the window down/up. That’s pressing a button. :lol:
Other than that, yes, your sentences mean the same thing.
And yes, in car without power windows, you could definitely roll up the window. 
Amy
PS
I drive a cheap car, so I always have to roll the windows up and down manually. 