If the engine on your car runs hot all the time this can be dangerous and cause serious engine problems. Over time, it could destroy your engine and you would have to replace it. Before this happens, below are two things that can cause an engine to overheat, as well as what you can do to fix it.
Problems with Cooling Fan
One common reason of an overheating engine is a problem with the cooling fan. Depending on the type of transmission you have, the cooling fan is either operated electrically or a mechanical clutch causes it to spin. The fan will automatically turn on any time the engine reaches a certain temperature. This is usually when your car is idling, such as if you are sitting at a long red light or you are stuck in traffic for a long period of time.
If the problem is your cooling fan, your car will overheat while it is stationary, but once you start driving the temperature will drop back down to normal again. Fortunately, the cooling fan is not an expensive part and easy to replace by a mechanic. If you have skills, you may be able to replace the cooling fan yourself.
Low or Bad Coolant
Another common cause of an engine overheating is low or bad coolant. This is the simplest problem to fix. There are many things that can cause low coolant. For example, there may be a leak in your radiator hose or the radiator itself or there may be problems with the engine's head gasket. Even a tiny hole can cause a leak. Check your car's coolant levels on a regular basis and add more if the level is too low.
Also, if the coolant has been in your car for a long period of time it may have gone bad. Over time, sludge will start to appear in the coolant and then the coolant will not be able to do its job well. This sludge could also get into your radiator hoses causing airflow problems. To take care of this, drain and then refill the cooling with fresh coolant. If it has been a very long time you may need to take your car to a mechanic to have the cooling system flushed professionally.
These are just two reasons why you may have an overheating engine. Talk to an auto service mechanic about other possible causes.