About a year ago, I noticed my 2018 Mazda 3 hatchback could use a little more coolant. I used Prestone AF2000 which says "for all vehicles and works with all coolant colors". Apparently my vehicle uses FL22 coolant. Is this something I should be concerned about? Should I throw out the Prestone? I never realized coolants can be so complicated.

 

Never mix coolants.