2002 Jeep Laredo Curious about the fact why I keep having t

My 2002 Jeep Grand Cherokee after a road trip to Canada from Mass and back is making an elctronic whining noise. It started overheating and steaming. Brought to the automotive place to be fixed. They said it was the fan and the thermostat. After having it fixed $500 later I am driving around town it is good for about a month. Now the Jeep is steaming from under the hood and the electronic noise is heard on and off again. Leaking radiator and loss of coolant going through 2 jugs of coolant a week. I Get the quote. $500 need new radiator, connectors, and new thermostat. Get the money and then have the automotive shop install new radiator, connectors, thermostat. Happy new Year! The Jeep is happy for about three days. Then the electronic whining is back the Jeep is beeeping and Beeping at me low coolant low coolant. I buy a new jug of coolant. I figure maybe it is because of the really cold weather it just needs a little. So I put some into the coolant tank. Well three days later. Low coolant. Low coolant. Arrghhh! Beeping and then more electronic whining. And whining. My question is what do you think its wrong. I just put a thousand dollars into my Jeep and I am just wondering what a mechanic would think the diagnosis would be hypathetically? Any theories would be appreciated. Thanks