I just now verified that your 97 ES uses the exact same radiator (same part numbers) as our 98 Camry V6. I went out into the garage, lifted the hood on the Camry, and looked down behind the radiator. I can see the drain plug on the back of the radiator at the bottom, on the left (passenger) side as you face the car. On our Camry, the plug sticks out pretty far and the part you grab is white -- very easy to see.
Actually, there are three different part numbers shown for the radiators on both your 97 ES and our 98 Camry V6. I'm assuming that they all have drain plugs but that might not be the case. Some cars don't have drain plugs on their radiators and are drained by removing the lower radiator hose.
Thanks VERY MUCH. I will check this out and get back to you, just FYI.
Thanks again.