Q: Coolant leaks while car is off, not overheating, new radiator!

I would recommend having your vehicle’s cooling system pressure tested by a qualified professional to determine the exact source of the coolant leak. This test will put your cooling system Under Pressure without the engine running to avoid the sound of the engine and the air of the engine cooling fan. This helps to easily spot cooling system leaks. Once the source of the leak has been discovered, you can then determine the correct repair plan.

It sounds like you may have a faulty water control valve, which may be prohibiting the flow of coolant properly through the heater core from the motor. Generally, when this happens you may notice the heater may not work or that coolant is leaking. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle.

If it looks like leaking from bottom hose then it is most likely the water pump leaking down the hose. Look at leak and follow it up to highest point to see if it is water pump? If cannot tell then have system pressure tested to see where the leak is coming from. Do not drive it or you may overheat engine and do more damage. The heater will not work correctly if low on coolant.