THERE SHOULD BE A PLUG ON THE BOTTOM OF THE RAD
driver'side lower radiator
If the radiator is original, LEAVE DRAIN PETCOCK ALONE !! You may NOT be be able to close it completely due to rust. Disconnect lower radiator hose instead.
You can find the 1991 Buick Skylark radiator drain plug on the bottom of the radiator. The radiator drain plug will be in the center of the radiator bottom.
where is the drain plug for the radiator on a 1992 buick regal custom
Is there a drain plug on a 2005 Buick century
The radiator drain plug should be close to the bottom of the radiator facing the engine. It could be a wing nut, or could be the type that is turned by a ratchet and extension.
Drain or petcock should be a the lower of rear of radiator or remove lower radiator hose
If there is no drain petcock then just remove the lower radiator hose.
Disconnect lower radiator hose if you can not find the drain valve. Drain water and antifreeze and flush it out good. Reconnect hose back up. Then add a gallon and 1/3 of anti freeze then finish with water.
Bottom corner of the radiator, facing the engine, typically opposite end of the radiator from the lower radiator hose.
On a 1997 Buick Park Avenue, the air conditioner drain hose is located under the hood and on the front of the firewall. It can be easily found by following the exhaust pipe from the catalytic converter on the passenger side up to the engine bay.
Drain plug is located right on top the right side of the engine where the radiator hose connects to the manifold. That is also where the thermostat is located.