Heater hoses and clamps, which usually go through the passenger side of the firewall to the heater core.Hose going to the coolant overflow tank, a hose that goes from just below the radiator cap to the overflow tank.Likely sources of an underhood leak include (listed roughly in order of cost or difficulty in fixing): It’s a good idea to wear protective glasses and gloves, and make sure to wash your hands afterward. If you can see the engine and get an idea as to the leak’s source, you might want to clean off any nearby suspected surfaces with a rag or paper towel and water before running the cold engine to find the leak. Make sure the air conditioner is off, however, as running it automatically turns on the radiator fan.Įven if you narrow down the vicinity of the leak, seeing where it’s coming from can be tricky, particularly on newer cars that have covers almost completely hiding the engine compartment. If you start the car the next morning and let it run awhile without moving it (make sure it’s not in a closed garage), the leak may appear - possibly as a stream or spray - before the radiator fan kicks on and blows the coolant all around. Nonetheless, putting cardboard under the car when it’s parked might be helpful in tracking down the leak. If you look in your coolant reservoir or remove the radiator cap (make sure it’s cool to the touch first), you can determine what color fluid you’re looking for.Ĭoolant leaks aren’t always easy to find, as air blowing through the front of the car (either due to the radiator fan or road speed) can spread coolant all over, and that means the puddle you see on the ground may not be directly under the leak. Exceptions are the heater core, which is located behind the dashboard, and the engine’s cylinder-head gasket, which we’ll get to in a bit.Ĭoolant is typically green or orange, but it’s sometimes pink or other colors. Most of the aforementioned components are found under the hood, so any coolant leaking from them will end up on the ground under the engine compartment. Unfortunately, that same pressure also amplifies any leaks. That pressure not only raises the boiling point of the coolant, it also helps keep the circulating coolant from bubbling, which could cause “hot spots” in the engine. Those components combined are part of the cooling system, which is kept under pressure by the radiator cap. Others … not so much.Ĭoolant can be found in the engine, the water pump at the front of the engine, the radiator, the radiator overflow tank and the heater core behind the dashboard, along with the valves and hoses that connect them. Some leaks can be fairly easy to find and fix. Coolant is also extremely poisonous, and its typically sweet smell attracts animals, so it’s best to track down and repair leaks promptly. If your car loses too much coolant, its engine could overheat. Several components in your car hold coolant, often called antifreeze, and any of them can get a hole or develop a leak.

Car not overheating but leaking coolant