Renovation of the Volvo D7D Engine in the Volvo L120E Wheel Loader

Volvo D7D engine overhaul in Volvo L120E wheel loader - comprehensive power unit service

The Volvo L120E wheel loader is one of the popular machines used in the construction industry, recycling plants, quarries, and material handling companies. The design of this machine combines high hydraulic system performance, a durable structure, and a reliable drive in the form of the Volvo D7D engine. This unit is a six-cylinder diesel engine with a displacement of approximately 7.1 liters, equipped with turbocharging and an electronically controlled injection system, designed to operate under heavy loads for many thousands of operating hours. The Volvo D7D engine was used, among others, in Volvo L90E, L110E, and Volvo L120E wheel loaders, as well as other construction machines from Volvo.

A Volvo L120E wheel loader operating in the Silesian Voivodeship, near Katowice, came to our service center. The machine operator reported a gradual loss of power, increased engine oil consumption, and heavy smoking when operating under load. Our mechanics conducted initial diagnostics directly at the customer's site, analyzing engine operating parameters, checking the intake system, and measuring compression pressure. Additionally, an endoscopic inspection of the cylinders was performed, which indicated excessive wear on the working surfaces of the cylinder liners and piston components.

After confirming the necessity of a Volvo D7D engine overhaul, the decision was made to remove it from the machine. Our mobile service reached the loader's job site, and using a crane provided by the customer, we safely extracted the power unit. The engine was properly secured and transported to our headquarters in Kojszówka, where the full verification and rebuilding process began.

Disassembly and detailed verification of the Volvo D7D engine

Upon delivering the engine to the workshop, we began the process of its complete disassembly. Each component was labeled and thoroughly cleaned to allow an accurate assessment of the degree of wear. Verification included inspecting the engine block, crankshaft, connecting rods, pistons, cylinder liners, and all timing gear components.

The crankshaft underwent measurements of journal diameters, runout inspection, and checking of oil channels. Connecting rods were checked for deformation, weight, geometry, and the condition of bolted connections. Particular attention was paid to the crank-piston system, as previous diagnostics indicated wear on the cylinders and pistons, causing loss of compression and increased oil consumption.

During disassembly, we confirmed excessive wear on the cylinder liners, signs of wear on the piston rings, and deterioration of the piston condition. Additionally, the Volvo D7D engine cylinder head was inspected. We performed a leak test in a heated water bath, inspected the valve seats, and measured the valve guides. This allowed us to determine the full scope of necessary regeneration work.

Repair and rebuild of the Volvo D7D engine

The rebuild process of the Volvo D7D engine included the regeneration of all components affecting the power unit's durability and performance. In the crank-piston system, new cylinder liners, pistons, piston rings, and a set of bearings were used. All components were selected according to the technical parameters specified by the engine manufacturer.

Following measurements, the crankshaft was prepared for further operation in accordance with the verification results. The cylinder head underwent full regeneration, including surface resurfacing, replacement of valve guides, and replacement of valves. The condition of the camshaft and its working surfaces was also inspected.

Inspecting auxiliary components is also of great importance during a Volvo D7D engine overhaul. We checked the turbocharger for radial and axial play, inspected the fuel system, electronic engine control components, alternator, starter, and other assemblies responsible for the proper operation of the Volvo L120E loader.

After completing all regeneration work, the engine assembly process began. The power unit is assembled in accordance with technical documentation and the appropriate tightening torques for bolted connections. We pay particular attention to cleanliness during assembly, correct alignment of timing components, sealing connections, and checking operating clearances.

Testing the Volvo D7D engine on an engine dynamometer

One of the most important stages of every overhaul performed by WIBAKO is testing the engine on a professional engine dynamometer. This allows us to run a test of the power unit before its reinstallation in the machine, which represents a huge advantage over standard repair methods.

After assembly, the Volvo D7D engine was mounted on the dynamometer test stand and subjected to hours of trials. The first phase involved running for a minimum of 16 operating hours under a light load of approximately 20-30% of the nominal value. At this stage, we monitored operating temperature, oil pressure, the tightness of all systems, and the stability of engine parameters.

Following the successful completion of the break-in stage, we conducted further tests with repeatedly increasing loads until reaching operating parameters close to the real working conditions of the Volvo L120E wheel loader. We controlled the power achieved, the engine's response to load changes, the operation of the fuel system, coolant temperature, and turbocharger behavior.

The engine dynamometer allows for the detection of even minor irregularities that might only appear after installing the engine in the machine. As a result, the customer receives a proven power unit that has undergone real working conditions before leaving our workshop. This is particularly crucial for machines like the Volvo L120E, where equipment downtime generates high costs for the enterprise.

Installation of the Volvo D7D engine in the Volvo L120E wheel loader

After completing the tests on the engine dynamometer, the refurbished engine was transported from our headquarters in Kojszówka back to the customer near Katowice. Our mechanics installed the power unit using a crane provided by the machine owner. The installation process included precise positioning of the engine in the compartment, mounting the fixtures, connecting the drivetrain, and hooking up all installations.

During installation, necessary hoses and consumable parts of the cooling and air intake systems were replaced, new filters were installed, and the appropriate operating fluids were refilled. Particular attention was paid to the tightness of the fuel, oil, and intake system line connections, as even minor leaks can affect the durability of the newly overhauled engine.

The first startup of the Volvo L120E loader took place in the presence of our mechanics and the machine operator. We conducted a series of operational tests including working under load, monitoring engine parameters, checking for leaks, and evaluating the proper integration of the engine with the machine's systems. Upon receiving positive results, a protocol for the completion of installation and the handover of the machine for further operation was signed.

Post-overhaul service maintenance and application of the Volvo D7D engine

Every Volvo D7D engine, after undergoing an overhaul, is covered by a warranty and the option of ongoing service care provided by our team. We recommend the first mandatory inspection after 50 operating hours. This is not limited merely to replacing filters and oil but also includes checking the tightness of all connections, inspecting auxiliary components, and assessing the proper operation of the unit after the break-in period.

Subsequent service inspections are carried out every 250 operating hours, but not less than once every three months. Our mobile service for construction machinery travels directly to the customer, performing the necessary checks and operational maintenance.

The Volvo D7D engine is used not only in the Volvo L120E wheel loader but also in Volvo L90E and Volvo L110E models, as well as in other construction machinery requiring a durable and efficient power unit.

Service of Volvo D7D engines and construction machinery

WIBAKO specializes in comprehensive overhauls of diesel engines used in construction machinery. We perform engine removal and installation directly at the customer's site, carry out full component verification, regeneration, and testing on our own engine dynamometer. Thanks to this, we are able to provide proven solutions for users of Volvo L120E wheel loaders and other machines operating in the harshest conditions.

See also our completed projects regarding overhauls of other Volvo engines and the servicing of wheel loaders, excavators, and other construction machinery.