Anyone with a driver’s license is probably familiar with semi-trucks- you see them everywhere, and it’s not uncommon to see several during a single commute. But what you might not know is that they are very durable and last quite a long time, but not for the reasons you might think.
Why do semi-trucks last so long? Semi-trucks typically last longer because their engines are designed differently than the engine of an average vehicle. The engine housed within a semi-truck is about 6 times the size of a standard car engine and can tolerate almost a million miles in its lifetime. The engine of an 18-wheeler is built to last longer, especially since they endure more wear and tear during their lifetime than a standard vehicle does.
Semi-trucks usually last longer due to the differences in the components of a diesel engine. There are several differences between the two, but they can be lumped into three main categories: differences in design, differences in fuel, and differences in use.
What Specifically Allows Diesel Engines to Last Longer?
Diesel Fuel Helps the Engine Run Smoothly
The most significant difference between the two types of engines is the type of fuel used to run them.
- Diesel
- results in less cylinder wear over time due to the makeup of the fuel
- lubricates the engine and allows it to run smoothly
- Gasoline
- does not lubricate the engine well and ends up deteriorating the engine.
- Prevents the engine from getting good oil flow and running smoothly
Diesel fuel is a lighter oil than gasoline, and it is also not flammable like gasoline is. In addition, gasoline burns much quicker than diesel. Diesel packs more energy than gasoline, increasing its efficiency. A gallon of diesel has 30% more energy than a gallon of gasoline, leading to better gas mileage.
Once, diesel was considered better for the environment than gasoline, but improvements in engine technology make it so that it is no longer the case. However, overall, diesel is a lot safer for engines and does not cause as much damage from use over time.
Diesel Engines Experience Less Wear and Tear
Another main difference that allows diesel engines to last much longer is through their mode of operation. RPM stands for revolutions per minute and shows how fast a vehicle is operating.
- Gasoline engines
- 2000-3500 RPM
- Is running twice as fast and working twice as hard as a diesel engine
- Diesel engines
- 1300-1600 RPM
- A diesel engine is working at a much slower rate than a gasoline engine
Through this statistic, it is easy to see why gasoline engines wear out much faster than a diesel engine.
Additionally, the most wear and tear done on an engine occurs during the period of time when the engine is starting up and getting warmed up.
Typically, diesel engines are left running longer, and even during short periods of time when the engine is not in use. This is not typically done with gasoline engines. Instead, they start up several times a day, which causes more damage to the engine over time; therefore, more wear and tear is done on a gasoline engine, which is a contributing factor to the short lifetime in comparison to diesel engines.
Diesel Engines are Built for Longevity
The design of a diesel engine is different from that of a gasoline engine. Everything is much larger in size compared to a gasoline engine, mainly because 18-wheelers are required to do heavier work than a standard car. Therefore they require more durable components. In addition, larger parts allow for better ease of oil flow.
Speaking of oil, a diesel engine also holds a much larger quantity of oil than gasoline engines. Most gasoline engines hold only about a gallon, whereas diesel engines hold close to 10 gallons. Diesel engines are gear based, meaning that the system can continue working even if something fails. Only after multiple failures or one catastrophic failure will the engine cease functioning.
Diesel engines also have multiple thermostats to reduce the chance of the engine overheating, whereas most vehicles fueled by gasoline only have one. There is also a special valve within diesel engines that help to lubricate the engine to keep it running smoothly.
Overall, the main difference within the design of the engine in a semi is that it is designed to prevent mishaps and breakdowns-it is built to withstand more and last longer than a standard gasoline engine.
Myth: Diesel Engines ALWAYS Last a Long Time
Despite popular belief, diesel engines are not guaranteed to last longer than an average gasoline engine. Like anything else, it needs to be taken good care of in order to maintain it’s longevity.
The most common reason that diesel engines do not live to their full expectancy is due to overheating from improper use. Many commercially used diesel trucks receive regular maintenance, more often than the average gasoline vehicle. Frequent maintenance is necessary to maintain the quality of the engine, as it is required to work harder than a gasoline engine.
The Big Three: Keeping your Diesel Engine Running Smoothly
The key to maintaining a healthy and quality diesel engine is in three main components- lubrication, cooling, and clean fuel. Each of these is crucial to the life of the engine and must be done regularly to preserve the longevity of the engine.
Lubrication
One of the most crucial aspects of a healthy engine is whether or not it is lubricated. If it is not, then it will not run smoothly and can experience trouble starting, breakdowns, and other issues.
- Ways to promote good lubrication
- Let the engine run for several minutes once being turned on
- Leave the engine running if not in use to prevent multiple starts
In addition, the oil should be changed regularly, as with any other engine. The time table for an oil change varies from engine to engine, but the average interval in a diesel engine is every 100 hours.
Cooling
In terms of cooling, most engine problems occur because of the cooling system. Since diesel engines work so hard, they have a tendency to overheat, which can cause a ton of problems. The exhaust should be checked often to ensure that it is working properly. Issues with the cooling system can result in long term problems. The cooling system should be inspected and receive proper maintenance once every year to ensure that it is working properly.
Clean Fuel
One crucial guideline to follow when working to promote the longevity of a diesel engine is using an additive. Utilizing a diesel fuel additive will help to keep the engine system clean and enable fuel to flow freely. Having clean fuel in a diesel engine is crucial to function.
If fuel is contaminated, it can actively erode the engine and cause permanent damage. Many companies now provide filtration systems in order to maintain clean fuel flowing within the engine and prevent damage from occurring due to unclean fuel.
Additives also help to preserve the engine and promote optimal performance. Staying on time with oil and filter is a must as well, much like with standard vehicles. Regular maintenance and monitoring will ensure that the engine is kept in good shape and maintained to last to its full functional capacity.
In essence, when taken care of properly, diesel engines can last a very long time and accumulate almost a million miles.
