Reasons Why a Car Overheats

Engine overheating is a fairly common problem that, if severe, can seriously damage a vehicle's engine. Although the potential causes of engine overheating are numerous, there are a handful of causes that are exceedingly common. What follows is a brief list of the most common reasons why a car overheats.

Bad Thermostat

  • An engine thermostat controls the flow of radiator fluid into a vehicle's engine. A bad thermostat, especially one that fails to open, can prevent radiator fluid from entering (and cooling) a running engine, which can cause an engine to overheat.

Faulty Radiator

  • A vehicle's radiator cools circulating engine coolant, which helps to maintain normal engine operating temperature and prevent overheating. A bad or faulty radiator can lose its ability to cool, or radiate, circulating engine coolant, which can cause an engine to overheat.

Bad Water Pump

  • A water pump is responsible for pressurizing and propelling engine coolant throughout a vehicle's engine and cooling system. Pressurized and fast-moving engine coolant is better able to absorb engine heat and reduce engine operating temperature. A bad water pump can prevent adequate coolant flow and pressurization, which can cause an engine to overheat.

Low Coolant Level

  • An adequate amount of engine coolant is necessary to absorb internal engine heat and carry it to the radiator, where the heat gets radiated into the outside air. A low engine coolant level allows engine heat to build up, which can cause an engine to overheat.

Bad Radiator Fan

  • A radiator fan helps to cool engine coolant as it filters through the radiator, especially when a vehicle is stopped and/or traveling at low speeds. A bad or faulty radiator fan can prevent adequate cooling of circulating engine coolant, which can cause an engine to overheat.