Coolant disappearing?

[Billymanjoe]

I got a 1991 LS400 and it was running fine until sometime last week. I drove about 10 minutes at around 50 mph and when I parked, the car started smoking under the hood a little bit. I checked under the hood and the coolant tank was pretty low so I waited about 3 hours and when I came back, I topped off the coolant tank and drove home with no issue. 

 

The check engine light was on but I made the mistake of paying it no mind. 

 

Until today, it ran fine and took me to and from work and school several times. I took my mom out to do an errand that was 5 minutes away. When we get there, the car starts smoking again but it's not much. It's putting out white smoke and it goes away pretty quick. I drive home and it starts smoking again so I get concerned. When I come home I let it cool for another 3 hours before checking the coolant tank again and it's almost empty. I top it off again and I go to pick up my little brother from school. Before we even make it back home, the front of the car starts whistling and the car starts overheating.

 

When I pull into the car port, white smoke starts pluming out the front left fender. When I pop open the hood, I notice the smoke isn't coming out from the engine but underneath the coolant tank. 

 

I don't think it's a coolant leak because when I park, there aren't any puddles or anything on the ground when I leave. What could it be?

 

Attached are pictures of where the smoke was generally coming from