[tinkering]

My 1996 Chevy 3/4 Ton 4X4, according to the manual, should use DEX COOL (1996 to 1998 inclusive). I was unaware of this, and I think the previous owners may have been too (there was a jug of regular AF in the truck). I have been adding regular ethylene glycol for a few years. Have I caused any serious damage in doing so; should I do a flush and replace it with DEX COOL? Is it time sensitive now; do I need to move ASAP?