Overheating

What Causes Engine Overheating?

Prevention of engine overheating and knowing the basics of why engine overheating occurs is always better than having to resort to temporary and quick fixes or worse, major engine repairs. Below are some usual causes of engine overheating. By knowing these, you become better armed in preventing and treating engine overheating problems.

Inadequate Water/Coolant Supply

This is actually one of the most basic causes of engine overheating. People tend to forget that water and coolant should be replenished from time to time. Always check if the water/coolant level is at the appropriate level. Moreover, keep the ratio of water and coolant at the appropriate proportions as too much coolant could actually contribute to engine overheating.

Coolants and antifreeze are actually less effective than water in cooling off the engine. However, these fluids freeze at lower temperatures and boil at higher temperatures so it is recommended that you put this in with the water in the cooling system. Moreover, coolants or anti freeze fluid prevents corrosion from occurring inside of the engine block as well as provides lubrication for the water pump. Unlike pure water, coolants prevent the radiator and the engine’s small water jackets from rusting.

The recommended ratio between the coolant and the water in the cooling system ranges from 50-50 to 35% coolant and 65% water depending on the climate at the place where you live or where you’ll be suing your automobile. Moreover, the effective life of coolants is more or less two to three years so you’d have to replenish it once in a while.

Busted Radiator Cap

A busted radiator cap is also one of the most common culprits in engine overheating. The cooling system is designed to be a pressurized closed system and one of its weaknesses is the radiator cap. Water under pressure boils at a higher temperature and thus is more effective in transmitting heat. When water in the cooling system reaches the boiling point, it generates air – and air is not as effective as water, as you know. Moreover, air inside the cooling system can displace water and coolant and force them out through the overflow tank or worse, the radiator cap or other such leaks.

This is why it is recommended that you use the rated radiator cap in order to be assured that it will be able to maintain its rated pressure. The rated radiator cap can be determined by looking for the information in the owner’s manual. Moreover, check the underside of your current radiator cap and see if it the cap gasket is still in good working condition. This gasket is what contains the pressure in the cooling system so if the radiator cap is missing, cracked or brittle, you should replace it as soon as possible.

A leaking radiator gasket may also be the reason why your cooling system leaks fluids especially after engine shutdown. This is due to the fact that with the engine off, the water pump stops the circulation of water through the engine block. Without this stimulation or circulation, the water that remains in the engine block gets hotter and, in some cases, actually boils. The air produced in this case displaces some of the liquid into the overflow tank. If the overflow tank becomes full, water is forced through the leak in the cap.

Radiator Hose Restriction

The radiator hose can also cause your car’s engine to overheat. This is especially true if there are pinches or kinks on it that restrict the water flow through the cooling system. Cracks or leaks on the radiator hose may also account for the loss of cooling fluids. In some cases, the spring that holds up the shape of the hose may be rusted or broken.

If your automobile’s radiator hose is damaged in any way, replace it at the earliest possible opportunity.

Wear and Tear on the Fan Belt

The fan belt on most cars (especially the serpentine-type belts that are found on newer car models) is used to drive several important components such as the water pump through the crankshaft pulley, the power steering, the A/C, the alternator and sometimes the fan. The upside of this type of belt is that it runs at a quieter mode than the older types of fan belts. The downside is that a failure in the fan belt lets engine overheating set in fact (in a matter of minutes, actually) because several key components of the cooling system depend on the fan belt for power.

The water pump, for one, will cease from pumping water in and out of the engine block. This means that the heat from the engine will no longer be able to reach the radiator and from there, get dissipated or released. Moreover, unless the car is traveling at an adequate speed for the air flow to dissipate the heat, the inoperability of the fan will also cause the engine to overheat.

To prevent this from happening, you must have a set of spare fan belt in your car. More importantly, however, you must know how to replace the fan belt in case the installed fan belt breaks down. You should also constantly monitor the condition of the fan belt and check it for cracks. Replace the automobile’s fan belt every four or five years (or even less if you are living in more temperate regions).

Inefficient Thermostat

The thermostat in the cooling system is the device that is responsible for controlling the amount of water and coolant that goes through the engine block. This device increases or decreases the amount of water and coolant that enters the engine block by monitoring the temperature of the coolant that flows through the engine block to draw heat off the engine and then cycles on toward the radiator in order to dissipate the heat into the surrounding air.

Because of this, it is recommended that you use the rated thermostat for your car in order to be assured of maximum efficiency. Some thermostats are inefficient in regulating the flow of coolant and water allowing too much or too little of the coolant or water to pass through and thereby causing the engine to overheat.

A quick fix for a busted thermostat is to temporarily remove the thermostat and run the car without it. This, however, can cause further problems especially for cars located in colder regions as, without a thermostat, the engine will find it hard to maintain its optimum operating temperature. This optimum temperature is needed to achieve efficient fuel burn and maximize the power produced. Moreover, an engine that operates at its optimum temperature also generates less pollution.

Leaking Water Pump

A leak in the water pump will also cause an engine to overheat because of the lack of coolant and water in the cooling system. The leak is usually situated in the bearing and the seal on the underside of the pump. What usually happens is that the bearing has gone bad and this acts to destroy the seal of the pump. Moreover, the leak is most visible when the engine is warm and the cooling system is operating under pressure and at high temperatures. Such a water pump leak is easily preventable, though, through regularly flushing and changing the coolant in the system; this will prevent rust formation and greatly increase the life of the pump.

Automatic Transmission Heat

Automatic transmission systems also generate more heat than standard transmission systems because the engine in automatic transmission systems constantly turns the torque converter. This torque converter serves as a pump for fluids and is never on neutral. This type of system demands that the engine of your car supply a constant amount of power; this consistent power production makes the engine run hotter. Moreover, because an automatic transmission system generates more heat than a standard transmission system, some of this heat dissipates into the engine block.

A preventive maintenance strategy for engine overheating caused by auto transmission is to have the transmission system serviced, have its fluid and filter changed regularly and have a transmission cooler installed.

Dirty Engines and Accessories

Having a lot of dirt and grease in your car’s engine will also lower its ability to dissipate heat into its surroundings. The accumulated grime and dirt will serve to retain the heat. Moreover, since chrome is a poor conductor of heat, chrome components actually serve to degrade the performance of your car; they do not actually enhance your car’s performance.

Instead of using chrome, try using aluminum accessories (for instance, use aluminum oil pans and valve covers). By doing this, you will help your engine maintain the optimum temperature as this metal is a good conductor of heat.

Fan Shroud Shape

One of the most overlooked aspects of engine performance is the size and shape of the fan shroud. Of course we all know that the radiator fan is the device responsible for taking away the heat from the water and the coolant by transferring this to the air that the fan generates. Lack of flowing air from the fan will cause the engine to overheat.

The fan shroud, however, multiplies the efficiency of the radiator fan by streaming the air through the radiator rather than around it. This results in the air drawing in more heat than usual and thus cooling the engine more efficiently.

A general rule here is to have a fan shroud that is a little larger than the diameter of the fan and a shroud that covers more or less half the width of the fan blade. Moreover, it should completely shroud the fan and the radiator to effectively tunnel the air through it.

Try to install the biggest fan too without compromising space for the other elements under the hood like the belts and hoses. A larger fan means more air flowing and more air means more heat dissipated.

The type of fan will also affect vehicle cooling performance. A good example of this is the clutch fan which is capable of turning faster than what the engine gives it at higher vehicle speed.

Head Gasket Leak

A leak in the head gasket may also severely affect the performance of your car’s water pump and engine. This is because when there is a leak in the head gasket, the coolant might be mixing with the oil and thus elevating the overall effective temperatures of the engine. Moreover, if the coolant is finding its way to the combustion chamber, this might explain why there is always a need to replenish the coolant every once in a while. To resolve this problem, you can try a leak stopping additive or have the head gasket replaced.

A leak in the head gasket might also force combustion gases into the coolant. This means that for some cars with a specific engine configuration, the gases might find a way into the water pump where they get trapped. When this happens, the pump will stall and this presents a problem as most water pumps cannot self prime. In most cases, it is best to just replace the head gasket immediately.

Friction and Crowding

Of course, you must also remember that internal engine friction could also account for higher than normal engine temperatures. Look for leaks and regularly change the oil on your car engine to minimize internal friction. Moreover, crowding of the engine components under the hood of your car may also account for the excessive engine heat. Make sure that there is enough ventilation under the hood to prevent this.

Tuning and Other Possible Reasons for Engine Overheating

Regular engine tuning could also go a long way in keeping your car’s engine heat in control. This is because air/fuel mixture and timing as well as spark all affect the effective that the engine generates. Another possible reason for engine overheating is the thickness of the engine’s cylinder wall and engine bores resulting in the inability of the engine to shed off heat efficiently.