Repair of the Liebherr D924 Engine in the LTM 1055-3.1 Crane: A Comprehensive Service Process

Introduction

The Liebherr LTM 1055-3.1 mobile crane is a modern machine used in construction, assembly, and industrial work. This model is characterized by high mobility, a telescopic boom, and reliability in daily use. In this case, our service was called to repair the Liebherr D924 engine, a diesel engine with a power range of 120-150 kW. This engine is a four-cylinder unit installed in many Liebherr machines. The repair was necessary due to cylinder and piston wear, which manifested as a drop in compression, smoking, and increased oil consumption.

Liebherr has been producing mobile cranes for years, known for their quality and precision, and the D924 series engines are proven designs with high durability. However, after long-term operation and high mileage, they also require professional refurbishment, which is provided by WIBAKO – a specialist in diesel engine and construction machinery service.

Preliminary Diagnostics

During the first inspection, difficulties with starting, a drop in power, and visible smoking were noted. Our technicians measured the compression on all cylinders and performed a cylinder leak test. We also used an endoscopic camera, which confirmed excessive wear of the cylinder walls and damage to the piston rings. The diagnosis was clear – a complete overhaul of the engine was necessary.

Engine Disassembly

The engine disassembly took place near Katowice. Our mobile service arrived on site, and thanks to the crane provided by the client, it was possible to efficiently remove the engine unit from the crane frame. The process included disconnecting the cooling system hoses, air intake, fuel lines, and all accessory components. After securing all components, the engine was transported to the WIBAKO headquarters in Kojszówka.

Component Verification

A full verification was conducted in the workshop. The crankshaft was measured for runout and wear of the journals, the cylinder head underwent a leak test in a water bath, and the connecting rods were checked for twisting and cracks. The verification confirmed the wear of the pistons, sleeves, and rings, as well as the necessity to refurbish the cylinder head. The injection pump was sent to an external facility for testing on a test bench.

Refurbishment and Repair

Piston-Crankshaft System

The pistons along with the rings, cylinder sleeves, and bearings were replaced. The crankshaft was ground and reassembled after checking the oil passages.

Engine Head

The cylinder head underwent complete refurbishment – machining, replacement of valve guides and valves, as well as a leak test. The valves were lapped, and the seals were replaced.

Fuel System

The injection pump and injectors were refurbished and tested. Proper pressure and uniform fuel distribution were ensured.

Accessories

The turbocharger was checked for axial and radial play, and the starter and alternator were tested and cleaned. All components were prepared for reassembly.

Engine Installation

The engine installation in the Liebherr LTM 1055-3.1 crane took place again in Katowice. The engine was installed according to the manufacturer's standards. The process included precise connection of the hoses, fuel system, cooling system, and air lines. The intake piping and fluid lines were also replaced to eliminate the risk of leaks. After the installation was completed, thorough tests were conducted with the machine operator, checking the correct oil pressure, operating temperature, absence of leaks, and stable operation of the unit. The entire process concluded with the preparation of a handover protocol.

Engine Test on the Test Bench

Before installation in the machine, the Liebherr D924 engine underwent a full test on our engine test bench. This is one of the greatest conveniences offered by WIBAKO, as this service ensures that the unit meets all operational parameters after refurbishment. The test lasted over 16 hours under light load, followed by several tests under full load. This allowed us to confirm the proper functioning of the injection system, cooling system, and stability of the engine under maximum load. Such tests help to eliminate potential issues before installation in the machine, significantly increasing safety and reliability in further operation.

Thanks to the test bench, our clients gain assurance that the engine after refurbishment will operate like brand new. This solution is unique in the market of construction machinery services in Poland.

Engine Maintenance After Overhaul

After the overhaul, the client received detailed service recommendations. The first inspection must be performed after 50 operating hours, which includes filter replacement and checking the tightness of connections. Subsequent inspections are recommended every 250 operating hours, but no less than once every three months. This allows for maintaining high engine efficiency and avoiding more serious failures.

Machines with Liebherr D924 Engine

The Liebherr D924 engine is found in many Liebherr construction machines, including mobile cranes, wheeled excavators, and loaders. It is a proven power unit used where high reliability and power in the range of 120-150 kW are required.

Summary

The overhaul of the Liebherr D924 engine in the Liebherr LTM 1055-3.1 mobile crane was carried out comprehensively – from diagnostics, through disassembly, full verification, component refurbishment, tests on the test bench, to installation and commissioning. Thanks to WIBAKO's experience, the client received a machine ready for further intensive work, with a guarantee and assurance of long-term operation.

If you are interested in construction machinery service or Liebherr diesel engine service, contact us and find out why we are a leader in the industry.