There are seemingly unlimited options to choose from when purchasing a new car. Car buyers want to be sure they are investing in a product that will last. But what causes one car to blow after a few thousand miles while others can run for hundreds of thousand of miles with no problems?
It all comes down to the amount of stress that the engine has been designed to handle. Factors that contribute to engine stress include heat, fuel, engine material, and engine layout. Exploring each of these factors helps one understand the health and reliability of an engine.
H​eat
T​he main stressor an engine has to handle is heat. Overheating is one of the main reasons an engine will blow or die. W​hen an engine blows this means that there’s damage to some portion of the engine that causes it to need to be replaced or rebuilt.
Engines are designed to handle heat as each of the pieces are made to expand and compress with changes in temperature. However, each engine can only handle a certain temperature range before they will fail under heat stress.
Cooling systems are another key tool used by engineers to prevent overheating. The cooling system works by pulling heat from the engine through the coolant from the radiator. This dissipates the heat throughout engine reducing overall heat stress. However, if the cooling system is not efficient in how it dissipates the heat, some parts of the engine may deteriorate more quickly.
Oiling systems are also designed to mitigate overheating. They prevent extra friction from contributing to thermal stresses in the engine. Neglecting routine oiling will cause an engine to be less reliable.
Cooling capacity
Another factor that affects the reliability of an engine is the engine’s overall capacity. The more room an engine has for coolant and oil, the more power they have to fight against heat stress.
However, larger engines are not automatically the most reliable. There are other important factors to consider in engine reliability.
Fuel
T​here are two primary types of engines: diesel and gasoline. Generally speaking, diesel engines are considered to be the most reliable option capable of traveling long distances and towing heavy loads. As diesel is injected into the engine, it contributes to lubrication and minimizes friction.
Gasoline contributes to engine health in other ways. Often, gasoline contains detergents which work to clean the engine of grime as it runs through the engine. However, gasoline can also clean out oil meaning the engine will need to be oiled more frequently.
Engine material
The material used to manufacture the engine is also a key factor in engine longevity and reliability. The two main pieces of an engine are the head and the block which are sealed together by a head gasket. This head gasket is key to keeping oil and coolant from spilling into areas they should not go.
Aluminum and cast iron are the two most common materials used to manufacture heads and blocks. Cast iron is the stronger and cheaper option but does not dissipate heat as well as aluminum. Aluminum, though, is more expensive and expands more when heated.
Often, engines are made from a combination of metals such as a cast-iron block with an aluminum head. There are pros and cons to each of these material combinations.
Engine layout
T​he engine layout is determined by the number of cylinders and the way they are laid out with the engine pistons. Different engine layouts are designed to handle different amounts of engine cycles. An engine cycle occurs when the engine goes from cool to hot to cool. Some engines are designed to handle more engine cycles while other are designed to travel for longer distances at a time.
Overall, engine reliability is determined by the way the engine is designed to handle heat and other stress. The more stress it’s able to handle, the more reliable it will be.
