Diesel engines and gasoline engines may seem similar at a glance, but under the hood, they operate very differently. Because of this, the maintenance routines for diesel-powered vehicles vary quite a bit from those of gas-powered cars. If you drive a diesel truck or car, understanding these differences can help you keep your engine running longer, more efficiently, and with fewer surprises down the road.
Regular maintenance is crucial for both types of engines, but the approach and timing can vary in ways that are important to know.
How Diesel Engines Work Differently
The core function of both diesel and gas engines is to convert fuel into energy through combustion. However, gasoline engines rely on spark plugs to ignite a fuel-air mixture, while diesel engines use compression alone to ignite diesel fuel. This difference in combustion affects everything from fuel efficiency and power output to maintenance schedules and potential repairs.
Diesel engines are known for producing more torque and lasting longer than gasoline engines, which makes them a popular choice for trucks, heavy-duty vehicles, and commercial fleets. But they also operate under higher pressures and temperatures, which means certain parts experience more stress and require special attention.
Oil Changes Are Even More Important
Both engine types need clean oil to prevent wear, but oil changes are even more essential for diesel engines. Diesel oil is thicker and contains additives to handle soot, carbon, and high temperatures. It breaks down differently than gasoline oil and can become contaminated faster in certain driving conditions.
Missing oil changes or using the wrong type of oil in a diesel engine can lead to poor performance, increased emissions, or damage to components like turbochargers and injectors. Our technicians recommend staying on schedule with oil and filter changes based on the vehicle's use and mileage, not just the calendar.
Fuel System Maintenance Is Critical
Diesel fuel systems are more sensitive to contamination than gasoline systems. Water, dirt, or air in the system can cause serious performance issues. That’s why diesel engines require regular fuel filter changes, and in some cases, water separators need to be emptied or replaced as well.
Gasoline fuel systems are typically less demanding in this area, but diesel vehicles demand careful monitoring. Clean fuel is essential for proper combustion and injector function.
Glow Plugs vs. Spark Plugs
While gas engines use spark plugs to ignite fuel, diesel engines use glow plugs to help the engine start in cold weather. These small heating elements warm the combustion chamber so that the engine can compress and ignite the fuel more easily. Glow plugs wear out over time and need to be tested and replaced periodically, especially in colder climates.
Unlike spark plugs, glow plugs aren’t replaced on a routine basis, but they do need attention when hard starts or poor cold-weather performance begins.
More Emission System Complexity
In recent years, diesel engines have become more advanced to meet modern emission standards. Components like diesel particulate filters (DPF), exhaust gas recirculation (EGR) valves, and diesel exhaust fluid (DEF) systems are now common. While these systems are effective in reducing emissions, they require regular maintenance to work properly.
If ignored, emission-related components can clog or fail, triggering warning lights or forcing the engine into a reduced power mode. Keeping these systems clean and functioning correctly is a key part of diesel engine upkeep.
Diesel Engines Last Longer—If You Maintain Them Right
One of the biggest benefits of diesel engines is longevity. With proper care, many diesel engines can exceed 300,000 miles or more. However, that only happens with consistent maintenance, high-quality fluids, and attention to small issues before they become major repairs.
Skimping on care or using low-quality parts may shorten the lifespan and take away the reliability diesel drivers count on.
Gowen’s Automotive Repairs – Diesel Maintenance Experts in Fairburn, GA
At Gowen’s Automotive Repairs, we specialize in diesel engine service and maintenance for light-duty trucks and diesel-powered vehicles. From oil changes and glow plug testing to DPF cleaning and fuel system care, our team is ready to help you protect your engine and your investment.
Visit us in Fairburn, GA, and keep your diesel running strong for the long haul.