Some of the most common reasons to see coolant under the car are a leaking radiator hose, a bad water pump or a loose radiator hose clamp. Leaks can also be caused by a bad thermostat housing, a worn intake manifold gasket, a bad heater core, a daรขโ‚ฌยฆ the key to fixing the leak is to find it first. There are multiple ways we handle these problems as professionals, so here are a few tips.