Scotty, A great big Tennessee howdy to you!
I’m doing a complete coolant flush on some of my vehicles and noticed on my Walmart shelf, Prestone claims it’s good for 10 years or 300,000 miles and is backwards compatible with all other coolants. Normally I would just get the supertek (except for my Asian cars) because it’s cheaper. It only rates itself for five years and 150,000 miles. Do you believe Prestone‘s claim?
I don't risk it. Keep in mind that the coolant is cheap but the engine repair is expensive.
Will the smart thing be to use the Prestone but change it in six years or so?
If you use HOAT coolants, you should be good for 150k miles/7 years.
Just get whatever 50/50 coolant is on sale and change it every 3 years. Be done with it. Why do you use special coolant in Asian cars?
I put back in whatever came in it
That's the best thing to do, at the very least stay with the same chemical formulation if not the specific brand. If you were going to change to a new type antifreeze you'd want to thoroughly flush out all of the old stuff first.