If the front of the engine leaks coolant there is a blown head gasket. This requires immediate repair as it can lead to a blown engine if not managed appropriately.
Power steering hoses Pump Steering rack
With a helper go to a car wash. Spray around the door and windshield with the helper inside to see where the water is coming from. This is the easiest way to find the leaks and plug or repair them.
You need a new heater core.
Are you loosing water and if so you will need to pressure test the cooling system. Repair any leaks and replace the thermostat. Then check your cooling fans for proper operation.
The usual way to fix it is to run new pipes up in the attic and back down. There is no way to fix the pipe under the floor. This is for supply lines only, drains require busting out the floor. Epoxy coating can be done if breaking the floor is absolutely not an option. It is often more costly than a spot repair, and is rarely if ever covered by insurance, but does not require the breaking of the concrete. It is also a good option if the pipes are deteriorating and are likely to continue developing leaks. Rerouting is a good option if you are in a climate that is not likely to freeze.
repair it or get a new one.
I plan to caulk mine shut. THe repair estimate was $9k.
it leaks fluid.
repair the leak
Find where it is running out and repair the cause.
For one of Miles' challenges, he askes you to find leaks around the barnyard and repair them. All the leaks look the same, so you won't have to worry about trying to find different looking ones. Most of the leaks are found around by the perimeter of the barnyard. (From what I remember there are no leaks anywhere else, just the barnyard.) Follow the fence of the barnyard around the whole entire space until you repair all the leaks.