My 2011 Hyundai Santa Fe came with the Hyundai OEM green coolant. I bought a Prestone coolant (neon yellow color) because the coolant in the expansion tank is low. Is it safe to mix those two coolants? (Prestone bottle says it's guaranteed for all vehicles (American/Asian/European)) Thank you!
If it's only slightly low (say, less than a half liter, conservatively), I'd just add some distilled water and call it good. You don't want to do this repeatedly between coolant flushes because you'll dilute the mixture too much. However, if you're routinely having to add coolant you have bigger problems.