Semi Truck Engine Parts Diagram: A Quick Visual Guide for Non-Mechanical Staff and Clients

If you manage a fleet of diesel trucks or work with heavy-duty trucks, understanding a semi-truck engine can be challenging, especially for non-mechanical staff and clients. 

In the guide below, you’ll learn about crucial components like the cylinder block, fuel system, and oil filter, along with several other essential parts. By the end, you’ll clearly understand how these parts work together to power a semi-truck, along with the basics of keeping them in good condition.

Cylinder Block

The cylinder block is the heart of a semi-truck engine, housing critical components like cylinders, pistons, and the crankshaft. This heavy-duty truck part is essential for engine stability and strength.

The primary purpose of the cylinder block is to contain the combustion process. It converts fuel into power that drives the truck. The block also channels coolant to regulate the engine’s temperature, ensuring it doesn’t overheat.

Proper maintenance practices include checking for cracks or wear, and ensuring coolant levels are adequate to prevent overheating. Using high-quality oil helps lubricate moving semi-truck parts, reducing friction and wear. Regular inspections can prevent costly repairs and keep your semi-truck running smoothly.

Fuel System

The fuel system is a critical part of a semi-truck engine, storing and delivering diesel to the engine and ensuring efficient combustion.

The main components of the fuel system include fuel tanks, fuel filters, and injectors. The fuel tanks store the diesel. The fuel filters remove impurities, protecting the engine, and the injectors spray fuel into the cylinders for combustion.

For maintenance, regularly replace fuel filters to prevent clogs. Check for leaks in the fuel tanks and lines. Ensure injectors are clean for optimal performance. Using high-quality diesel reduces the risk of engine problems. 

Oil Filter

The oil filter keeps the engine oil clean by removing dirt and debris. Clean oil lubricates engine parts, reducing friction and preventing wear. Without a good oil filter, contaminants could damage the engine.

During every oil change, ensure that you change the filter as well. Use high-quality filters to ensure they trap impurities effectively. This simple step can extend the life of your semi-truck engine and improve its performance.

Coolant Reservoir

The coolant reservoir stores extra coolant, which helps regulate the engine’s temperature, ensuring it doesn’t overheat. This is especially important for long hauls where the engine runs for extended periods.

To maintain the coolant reservoir, inspect the coolant level and top it up as needed. Use the right type of coolant for your truck. Examine the reservoir for cracks or leaks. Keeping the coolant system in good shape prevents overheating and protects the engine.

Steering Box

The steering box is a pivotal part of a semi-truck’s steering system, converting the driver’s steering wheel movement into turning motion for the wheels.

The primary purpose of the steering box is to ensure precise control of the trucker’s direction. It plays a vital role in the safety and handling of the vehicle, especially for heavy-duty trucks during long hauls.

For maintenance, look for leaks in the power steering fluid. Inspect the steering box for any signs of wear and damage. Lubricate the moving parts to ensure smooth operation. Keeping the steering box in good condition ensures safe and reliable steering for your semi-truck.

Air Compressors

Air compressors are vital for a semi-truck’s braking system. They generate the air pressure needed to operate air brakes, which are necessary for heavy-duty trucks.

The main purpose of the air compressor is to provide compressed air for the truck’s air brake system. Without it, the brakes wouldn’t function properly, making it unsafe to drive.

Maintenance procedures dictate that you look for leaks and ensure the compressor is running efficiently. Examine the air filters and replace them as needed to prevent contaminants from entering the system. Check the drive belt for wear and tension. 

Fan

The fan is a crucial component of a semi-truck engine’s cooling system. It helps regulate the engine’s temperature by drawing air through the radiator.

The fan’s main purpose is to keep the engine cool, especially during long hauls. It prevents overheating by ensuring a steady airflow over the radiator, which dissipates heat from the coolant.

Inspect the fan blades for damage or wear, and ensure the fan belt is in good condition and properly tensioned. Examine the fan clutch to ensure it engages and disengages correctly. Keeping the fan in good shape is key to preventing engine overheating and ensuring your semi-truck runs efficiently.

Timing Chain

The timing chain synchronizes the crankshaft and camshaft rotation, ensuring the engine’s valves open and close at the right times.

The main purpose of the timing chain is to maintain precise timing in the engine. This ensures efficient operation and optimal performance. It’s important to coordinate engine parts, including the fuel injectors and turbochargers.

When conducting maintenance, check for signs of wear or stretching. Listen for unusual noises, which could indicate a problem. Replace the timing chain according to the manufacturer’s recommendations. 

Torque Converter

The torque converter connects the engine to the transmission and transfers power to the drive shaft. Its main purpose is to allow the engine to run while the truck is stopped and transmit power when it starts moving smoothly. It also multiplies engine torque, making it easier to haul heavy loads.

Scan for leaks and ensure the fluid levels are correct. Use high-quality transmission fluid to keep it running smoothly. Regular inspections can prevent costly breakdowns and keep your semi-truck in top condition.

Do You Need Engine Maintenance for Your Semi Truck Fleet?

Each part of your semi-truck engine has a specific role and requires regular maintenance to ensure optimal performance. Maintaining these components can prevent costly repairs and downtime. Using high-quality parts and fluids will keep your engine running smoothly.

If your fleet is due for engine maintenance, Kyrish Truck Center Group offers comprehensive fleet maintenance services. We inspect the drive shaft, alternator, and EGR system, replace equipment parts, and service the fifth wheel. 

Additionally, our experts also handle HVAC repairs and fit new mud flaps. Whether you drive a Mack or a Volvo, we keep your fleet road-ready. Contact us today!