I am having my coolant fluid changed next week. When my mechanic popped the radiator cap he noticed the coolant was green (Prestone perhaps?) Was a strong green, clean as clean can be. I know these cars are recommended to use Dex-cool and color has little impact on what's actually in the system right now but my question is what if perhaps sometime throughout time the previous owner converted to regular coolant. Is this safe for the car. Also, is it an accepted practice?

 

Nissan Coolant is SUPER DARK GREEN...
Prestone is neon-bright green..

it's probalby OEM fluid in there.. also.. don't use dex-cool.. ur car will blow up..