coolant drain and fill
 

Hi,
I have a 2013 V6 Coupe that is due for coolant change. I just plan on doing a basic refresh and not a complete flush. If I just open the petcock at the bottom of the radiator and drain, how much new coolant will I need to go buy to refill? I guess I could just drain it to see, but I want to have the new stuff on hand first.
As always thanks.

Here is how you might solve your concern.
Look for the cooling system capacity in your vehicle owner's manual.
The radiator will usually drain about half. If you purchase a one gallon bottle and dilute to 50/50 as recommended, you end up with 2 gallons and that should fill the radiator.

Gee, now why didn't I think of that? Thanks