Possible Causes of Engine Overheating Problems

For drivers that see their temperature gauge creeping past the normal range and heading for the red zone, the first thing that pops into their head is “it must be the thermostat”. Although this is one possibility, more often than not it’s something else. This article will review root causes of engine overheating problems and talk about the different symptoms associated with each individual problem. For those that think it’s always the thermostat we’ll cover this part and the clear symptoms when it malfunctions.

Missing Air Dams

An often overlooked possibility of an engine overheating situation is a damaged or missing front air dam. This is a low hanging piece of molded plastic that scoops up air and diverts it to the radiator. Not all cars have air dams or require them. Most often these are included on vehicles with a sporty look to the front nose. A good example of where they’re used is on the Corvette and Firebird, where no visible grille is seen in the design. All air used for cooling enters from underneath.It’s common for these to be damaged because they are the lowest hanging part. Air dams are made of plastic and easily destroyed by concrete parking curbs, placing them near the top of possible causes of situational engine overheating problems. A common description of symptoms from drivers missing one would be overheating at highway speeds but not at idle. When the part is missing all of the air passes under the vehicle instead of up through the radiator. The large amount and speed of air passing underneath can actually create a venturi effect pulling air away from the radiator.

Water Pump Problems

Although considered less common by professional mechanics, a problem with the water pump can cause an overheating condition. Since the water pump is responsible for providing flow and pressure to the system, internal malfunctions can reduce the efficiency of the cooling system. These can be difficult to diagnose because technicians will naturally look to other areas for the root cause of the problem.Often when the water pump causes an overheating condition it turns out to be a problem with the impeller. If engine coolant services are ignored long enough, the fluid can become acidic and eat away at metal impellers quickly. In the case of a plastic impeller, it’s possible for the part to become brittle and break loose from the drive shaft. In both of these situations, the impeller looses the ability to push coolant. A mechanic can diagnose this by verifying the movement of antifreeze in the system.

Radiator Problems

There is no question when it comes to the job of the cooling system, which boils down to removing heat from the engine, the automotive radiator is one of the most important components of getting this job done. By design, the ability for radiator to transfer heat to the incoming air is facilitated by a steady even flow of coolant through the network of tubes surrounded by fins. Since these are the smallest places in a coolant system they are vulnerable to clogging.Although corrosion buildup is capable of blocking the radiator tubes, it is more likely to be clogged by foreign materials installed by the driver or mechanics. When stop leak is incorrectly installed it can block complete sections of the radiator core. Another common radiator problem is with debris blocking airflow through the radiator. Things like plastic bags, paper plates and trash can cover large sections therefore eliminating them from the heat transfer process.

Thermostat Issues

A thermostat malfunction can cause an overheating situation. Generally speaking, the thermostat is a simple device and because of its basic design doesn’t fail often. When this part malfunctions, it can get stuck in the open position causing the vehicle not to heat up. It can also be stuck in the closed position causing an overheating situation. If the valve is stuck open, drivers will complain of lack of heat and poor fuel economy. Hopefully your automobile has a temperature gauge because there is no separate warning light for an engine that runs to cold.When the thermostat is stuck in the closed position an overheating situation can occur quickly from the first drive cycle. A defective thermostat has clear-cut symptoms and diagnostic procedures. Since its location is in-between the engine and the radiator upper hose the engine side will be hot and the upper radiator hose will be cold. Therefore, if the engine temperature gauge is in the red and the upper hose is cool to the touch this would be a good sign the thermostat needs to be tested.

In conclusion, it’s safe to say that the thermostat could be the cause of your engine overheating problems, but many other things can cause this condition as well. A skilled technician will approach the situation with an open mind and treat the malfunction individually. Coolant flow problems like a stuck closed thermostat or defective water pump impeller are just as likely as airflow problems. Air dams scoop up air traveling under the car and push it up to the radiator so the cooling fans can pull it across the core. Any break in this chain of events can cause vehicles to run hot.