My Buick lucene keep losing water

You have a big antifreeze leak somewhere.

Typically the sneaky L tubes made of plastic cause a leak that’s difficult to see at first. One way to see it is to get under the vehicle and in the passenger side you should see some caked coolant if enough a polled up and dripped down the passenger side of the engine block behind the pulleys there will show small damp spots as it dries quick. It’s typically the connectors as they are garbage plastic quick failure and first place to look. I suggest this video and EAN THE PORTS as good or better than this gentleman with whatevr it takes to polish the ports and get the Dorman part number from the video too.. good luck.. here ya go: https://youtu.be/HHWrN3nZHWA