CAN I USE AUTO LAB PREMIXED ANTIFREEZE COLLANT IN A 1993 SIERRA?

If you have Dexcool in it, you don't want to mix it with standard fluid unless it's labeled universal (and even then, best to stick with ONE type). You can tell if it's orange or orange-red it's got nitrates, which is DexCool. You can remove ALL the coolant and switch to another type, but dex cool is supposed to lead to longer pump life- but studies have shown that a well maintained system with standard ethylene glycol (green) stuff works just fine.

Thankyou very much.