HelloCustomer I'm not sure what to say except that I have never had much difficulty finding the drain cock. One tidbit I can give you is it is usually on the engine side of the radiator and will turn easily. Here is what GM service information has to say about it.
The radiator is a heat exchanger. It consists of a core and 2 tanks. The aluminum core is a tube and fin crossflow design that extends from the inlet tank to the outlet tank. Fins are placed around the outside of the tubes to improve heat transfer to the atmosphere.
The inlet and outlet tanks are a molded, high temperature, nylon reinforced plastic material. A high temperature rubber gasket seals the tank flange edge to the aluminum core. The tanks are clamped to the core with clinch tabs. The tabs are part of the aluminum header at each end of the core.
The radiator also has a drain cock located in the bottom of the left hand tank. The drain cock unit includes the drain cock and drain cock seal.
The radiator removes heat from the coolant passing through it. The fins on the core transfer heat from the coolant passing through the tubes. As air passes between the fins, it absorbs heat and cools the coolant.
Cooling System Draining and Filling
Coolant and Battery Tester
Caution: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.
Tighten Tighten the radiator drain cock to 2 N·m (18 lb in).
Tighten Tighten the drain plugs to 18 N·m (13 lb ft).
Important: Use a 50/50 mixture of DEX-COOL antifreeze and clean, drinkable water.