Need to check the 4 corners on the intake manifold. It is common for the intake to leak engine coolant.
R134a
full coolant system is about 12liters dry.
Dex-cool
It could be the coolant overflow tank that is leaking.
It uses Dexcool.
r-134A
Aprox 12 qts.
11.7 quarts
The heater core has failed and is leaking engine coolant.
The engine block coolant drain plug on 4.3 liter Chevy Blazer is located on the bottom of the engine, near the oil filter. It allows coolant to be completely drained from the block during maintenance.
Originally it would have had DexCool.
Aprox 12 qts, it varies if you have ac or not.