Coolant leaking from the back of the engine block

Hello, I'm Danny.

The first thing I suggest is to perform a cooling system pressure test. It is basically a pump that pressurizes the cooling system with the engine off. You can perform this with the engine off and cold to reduce injury. Once the system is pressurized you will be able to see where the leaks are coming from. If you don't have access to a pressure tester most auto parts stores have a tool loaner program and can rent you one. Here are tutorials showing how to pressure test and how to replace a coolant temperature sensor.

https://www.2carpros.com/articles/radiator-pressure-test

https://www.2carpros.com/articles/how-a-coolant-temperature-sensor-works

https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor

While testing I find it better to fill the system with tap water so you don't waste expensive coolant until it is repaired. I've also attached pictures on how to replace the coolant temperature sensor if interested for your Windstar. Once you find the leak get back to us and we'll help with the repair. Hope this helps and thanks for using 2CarPros.