I believe it doesn't have one. To drain it you will have to take out the electric fan, take off the tranny cooler lines if it is an automatic & all the rad hoses. THEN TAKE OUT THE RAD VERY CAREFULLY.
bottom of radiator
The 1992 V-6 Pontiac Sunbird radiator drain plug, is located on the bottom of the radiator. The drain plug can be removed with a 5/8 socket.
In order to drain the radiator on a 2004 Pontiac GTO it is necessary to pull the lower radiator hose off. There is not a separate drain plug on this radiator.
I have a 2000 Pontiac Grand AM and radiator drain cock is located at the lower/front (not bottom) at the curbside of the radiator, you will need a hex key to back out petcock.
the rad drain plug is located on the drivers side behind the front bumper
there may not be one if there is is it on the bottom side and if it is not you candrain it by removing the bottom rad hose The 1999 Pontiac Grand Am does not have a radiator drain valve. To drain the radiator, remove the lower radiator hose. The engine should be cold and the water fill cap removed for venting. I have a 2000 Pontiac Grand AM and radiator drain cock is located at the lower/front (not bottom) at the curbside of the radiator, you will need a hex key to back out petcock. .
Look at the bottom or rear of radiator
on the radiator
The 1991 Pontiac Grand Am radiator drain plug can be found on the bottom of the radiator. The radiator drain plug will be in the center of the radiator bottom.
Drain the radiator of fluid, take the shroud off if it has one, take top and lower radiator hoses off the radiator, if automatic transmission you need to take the 2 lines that go into the bottom of the radiator off, unbolt the 4 bolts that hold the radiator in to the radiator support and pull the radiator out, to install new radiator just reverse the process.
The radiator petcock drain on a 1999 Pontiac Bonneville is on the bottom of the radiator. Look for a small black plug that looks like the plug found on a thermos or cooler.
Look at the lower or rear of radiator