Where is the radiator drain valve located on the 2000 chevy Impala. I need to flush & refill anti-freeeze.

I First, you must remove the black air deflctor that runs underneath the radiator across the car. Maybe about 8 bolts. Even then I couldn't find the drain plug at first. It is on the driver's side. Beneath the radiator there is a heavy metal Mounting bracket. Almost looks like a crossmember. About an inch in from the left (driver's) side bottom of the bracket there is a large round hole with a rubber grommet. In the center of this hole it the outlet of the drain. If you reach directly above it on the back side of the radiator, i.e. come around back on the bracket and looking forward, you will find the drain ****. It is black plastic and has 2 ****, not a full petcock handle. It is still hard to see, even after removing the air deflector. The air deflector is the one people knock off by running too far forward when parking. I hope this helps .Remember the 2 or 3 vents at top of radiator hoses when refilling the system.
The radiator does have a hard to see drain plug on the left drivers' side. There are 5 10MM screws holding the air deflector on. The block has removable plugs, one 14MM hex next to the oil filter and one in about the same location on the other side of the block toward the firewall under the exhaust manifold.

The textbook method is to remove the drain plug on the bottom of the radiator.

Most drain plug is make of inexpensive nylon/plastic and it may fall apart while you turn it.

The professional method is to loosen the lower radiator clamp and drop to lower radiator hose.

Drain the coolant onto a large drain pan and recycle the coolant

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