What type of coolent for 1999 chevy astro - 1999 Chevrolet Astro

Hello! Your van most likely still has the coolant that was in it from the factory - which would be DexCool. If you can see it in the coolant overflow, and it is orange-ish in color - it's DexCool (or possibly a DexCool-friendly brand). I would suggest a full, and thorough coolant system flush - and then refill with the green stuff. If your van does have DexCool - you CAN NOT mix it with anything that does not implicitly state that is compatible. If you do - it will harden and congeal and ruin your coolant system - and perhaps even your engine.

Hope this helps!