# Repair of the John Deere 6068HF285 Engine in the Tesab 623CT Crusher

> The overhaul of the John Deere 6068HF285 engine in the mobile Tesab 623CT crusher is a comprehensive process that includes diagnostics, disassembly, repair, and testing on a dynamometer. Learn how to ensure the reliability and efficiency of the machine in challenging working conditions.

## John Deere 6068HF285 Engine Overhaul in a Tesab 623CT Mobile Stone Crusher

The Tesab 623CT mobile stone crusher is designed for crushing mineral materials, producing aggregates, and operating in demanding conditions on construction sites and at material processing plants. In these applications, drive system reliability directly affects the efficiency of the entire process. An extended engine downtime means not only an inability to crush material but also delays in completing work and difficulties organizing material transport.

The machine described here is powered by a six-cylinder John Deere 6068HF285 diesel engine with a displacement of 6.8 litres, belonging to the industrial PowerTech engine family. Engines of this type are used in demanding industrial applications where operational stability, adequate torque, and the ability to operate under sustained load are essential. The exact configuration of the engine version and its equipment should always be confirmed using the serial number.

In the Tesab 623CT crusher, the engine operates under conditions typical of machines used for aggregate processing. Variable load intensity, dusty environments, long operating cycles, and frequent changes in power demand make the proper condition of the lubrication system, cooling system, intake system, and mechanical components particularly important. Even gradually developing wear can lead to reduced performance and increased operating costs.

If the engine loses power, consumes excessive engine oil, or operates irregularly, diagnostics are necessary to distinguish between an auxiliary equipment fault and wear of the engine's internal components. As part of its diesel engine service, WIBAKO provides diagnostics, engine removal, overhauls, and installation of power units in construction and industrial machinery. An important part of the process is the ability to test the overhauled engine on an engine dynamometer before reinstalling it in the machine.

### John Deere 6068HF285 Engine Diagnostics Before Overhaul

One possible reason for qualifying the John Deere 6068HF285 engine for overhaul is the natural wear of components in the crankshaft and piston assembly. As operating hours accumulate, pistons, piston rings, cylinder liners, and bearings may lose their original properties. This can result in reduced compression, increased oil consumption, excessive crankcase blow-by, and a gradual loss of power. In a machine used for crushing materials, these symptoms may be particularly noticeable during extended operation under load.

The first stage of diagnostics involves gathering information from the operator about the machine's behaviour. Important details include starting difficulties, changes in oil consumption, the appearance of smoke, unusual noises, and situations in which the engine fails to maintain the expected operating parameters. The service history, oil and filter replacement intervals, and any previous repairs must also be taken into account.

Basic technical inspections are then carried out. These include checking the oil level and visible condition, inspecting the lubrication system for leaks, examining intake hoses, and checking the cooling system components. Filter inspections can provide additional information about the engine's condition. The presence of metallic contaminants in the oil or filter may indicate wear of interacting components, but further verification is required before a definitive diagnosis can be made.

If the symptoms indicate wear of the cylinders and pistons, the next step is diagnostics aimed at assessing the sealing of the combustion chambers. Depending on the availability of appropriate procedures and the condition of the engine, compression testing, cylinder leak testing, or inspection using a borescope may be performed. The results must be interpreted alongside the other symptoms, as a single measurement does not always provide a definitive assessment of the extent of the damage.

Before deciding on an overhaul, causes unrelated directly to mechanical wear must also be ruled out. A loss of power may result from problems with the air supply, fuel system, turbocharger, or charge-air cooling system. Therefore, diagnostics of the John Deere 6068HF285 engine in the Tesab 623CT crusher should cover both the mechanical components and the auxiliary systems responsible for proper engine operation.

### Removing the Engine from the Tesab 623CT Crusher

Once the need for an overhaul has been confirmed, preparations can begin to remove the engine from the machine. Work starts with securing the work area and immobilising the crusher. The power unit must be disconnected from the electrical installation and associated components in a way that allows it to be safely removed from the engine compartment.

The engine is removed using a crane provided by the customer. Before lifting begins, the mechanics check the engine mounting arrangement, the position of the lifting points, and access to the bolts and structural components. They also identify the hoses, connectors, and connections that must be disconnected before the engine can be removed. This preparation reduces the risk of damaging auxiliary components and facilitates subsequent installation.

The next stage involves disconnecting the fuel lines, electrical wiring, cooling system hoses, and air intake connections. Components intended for reuse must be properly protected against contamination and damage. Particular attention is paid to open hoses, ports, and passages through which contaminants could enter the lubrication, fuel, or intake systems.

The mechanics then undo the engine mountings and disconnect the remaining mechanical connections in accordance with the configuration of the machine. Before lifting the unit, they must ensure that no hoses, brackets, or other components remain connected or obstruct its removal. The engine is lifted in a controlled manner, taking its weight and centre of gravity into account.

Once the engine has been removed from the Tesab 623CT crusher, the accessible components in the engine compartment are inspected. This helps identify any signs of leaks, damaged mountings, worn hoses, and contamination around the cooling and intake systems. These findings are important during reinstallation because an engine overhaul alone will not resolve problems caused by faulty machine systems.

The removed John Deere 6068HF285 engine is prepared for transport to the WIBAKO workshop in Kojszówka, Poland. At this stage, it is important to protect all openings and connections to minimise the risk of contamination during transport. A list of auxiliary components requiring separate inspection or reconditioning can also be prepared.

### Inspection of the John Deere 6068HF285 Engine in the Workshop

Once the engine arrives at the workshop, a detailed assessment of its technical condition begins. The scope of the inspection depends on the symptoms identified in the Tesab 623CT crusher and the results of the initial diagnostics. The aim is to determine the actual extent of wear, identify damage, and prepare a list of the work required to restore the power unit to proper operating condition.

The first step is an external visual inspection. The mechanics check the block surfaces, joint areas, seals, mounting components, and accessible parts of the auxiliary equipment. They look for signs of overheating, leaks, mechanical damage, and other indications that may help establish the cause of the failure. If the engine's condition permits additional tests before dismantling, these may supplement the information obtained during the earlier diagnostic stage.

The engine is then dismantled into its individual components. The removed parts are cleaned and inspected, and their condition is documented throughout the process. The assessment involves more than visual inspection alone. Depending on the component, it also includes measuring working dimensions, evaluating clearances, inspecting mating surfaces, and checking whether the component meets the manufacturer's specifications.

Particular attention is paid to the crankshaft and piston assembly, including the cylinder liners, pistons, piston rings, connecting rods, crankshaft, and bearings. The mechanics look for seizure marks, scratches, excessive wear, and signs of inadequate lubrication. Cylinder liners must be measured to assess their wear and geometry. Pistons are inspected for damage to the crowns, piston ring grooves, and surfaces that interact with the cylinders.

The crankshaft undergoes a visual inspection and measurements of the journals and runout. The oil passages and bearing contact surfaces are also checked. Connecting rods are inspected for cracks, deformation, surface wear, and the condition of their bolted joints. The results help determine which components can be reused, which require reconditioning, and which must be replaced.

The cylinder head is inspected separately. The valves, valve guides, valve seats, and cylinder head mating surface are checked. Depending on its technical condition, a pressure test may also be carried out to identify leaks or cracks. The inspection additionally covers the lubrication system, timing components, turbocharger, and other systems that operate in conjunction with the engine.

Once the measurements are complete, the scope of the overhaul can be established and the appropriate parts selected. Decisions about reconditioning and replacement should be based on the actual condition of the components rather than solely on the presumed cause of the failure. This approach reduces the risk of overlooking damage that could cause the crusher to become immobilised again.

### Overhauling the John Deere Engine's Crankshaft and Piston Assembly

The crankshaft and piston assembly converts the energy generated by fuel combustion into the rotational movement of the crankshaft. Its condition directly affects compression, engine performance, oil consumption, and the service life of the entire power unit. In an engine operating in a stone crusher, maintaining the correct clearances and proper lubrication is particularly important because of prolonged operation under varying loads.

If measurements confirm excessive wear of the cylinders, pistons, and piston rings, the overhaul includes preparing the working surfaces and replacing or reconditioning components according to the inspection results. The dimensions and surface condition of the cylinder liners are checked. If liner replacement is necessary, it must be carried out while maintaining the correct installation dimensions. Once the work is complete, the parameters essential for proper interaction between the components must be checked again.

Pistons and piston rings require careful inspection. Worn piston rings can reduce combustion chamber sealing, increase crankcase blow-by, and raise oil consumption. Piston damage, in turn, may result from improper combustion conditions, overheating, or lubrication problems. Replacement parts must be selected for the specific engine version and the dimensions established during the inspection.

Inspecting the crankshaft makes it possible to determine whether its working surfaces remain within the required specifications. If necessary, the crankshaft can undergo appropriate reconditioning, provided its condition and dimensions permit this solution. The main and connecting rod bearings are also inspected, as they ensure proper interaction between the crankshaft and the other components. During installation, maintaining the correct clearances and keeping the oil passages clean are essential.

Before the assembly is rebuilt, all components must be thoroughly cleaned and checked for contaminants that could interfere with lubrication. During assembly, parts with specifications appropriate to the engine configuration are used, and the procedures prescribed for individual connections are followed. Careful inspection at this stage reduces the risk of premature wear after the engine is started.

### Inspecting and Repairing the Cylinder Head

The cylinder head of the John Deere 6068HF285 engine ensures proper gas exchange in the cylinders and maintains combustion chamber sealing. Its condition affects starting, smooth operation, performance, and engine temperature. During the overhaul, the cylinder head is thoroughly cleaned and inspected for damage, valve seat wear, and the condition of the valve guides and valves.

One important stage is checking for leaks. Depending on the design and the procedure used, a test can be performed to identify cracks or other defects. The cylinder head mating surface is also inspected. Any machining must take account of the permitted dimensions and the manufacturer's requirements, as improper surface preparation can adversely affect the sealing of the joint.

If required by the technical condition, reconditioning may include resurfacing the cylinder head, replacing valve guides and valves, and properly preparing the valve seats. The scope of work is determined after the measurements have been completed. Not every component needs to be replaced automatically, but leaving parts worn beyond the permitted limits can result in loss of sealing and the need to remove the engine again.

Once machining and the necessary component replacements are complete, the cylinder head is inspected again. The checks focus particularly on workmanship, surface condition, and sealing. Only after successful verification can the cylinder head be prepared for installation on the engine block. Proper cylinder head repair is an important part of a comprehensive overhaul because renewing the crankshaft and piston assembly alone will not ensure correct engine operation if the combustion chambers remain inadequately sealed.

### Inspecting the Fuel System and Engine Auxiliary Components

When overhauling an industrial engine, the work should not be limited to mechanical components alone. Proper engine operation also depends on the condition of the fuel system, turbocharger, charge-air cooling system, starter motor, alternator, and other associated components. This is particularly important in the Tesab 623CT crusher because a malfunction in any of these components can limit available power even after a mechanical overhaul has been completed.

The fuel system is inspected for leaks, contamination, and proper operation of the components responsible for fuel delivery. If the symptoms or diagnostic results indicate injection problems, the injectors and other components may require more detailed inspection. Depending on the design and scope of the repair, components requiring specialist testing are sent for examination on an appropriate test bench.

In electronically controlled engines, diagnostics of the electrical system and the signals transmitted by sensors are also particularly important. Before replacing components, it is necessary to establish whether the observed symptoms are actually caused by their failure. This helps avoid unnecessary costs and ensures consistency between mechanical repairs and control system diagnostics.

The turbocharger is checked for excessive play, the condition of the rotating components, and visible signs of damage. The oil supply and return lines, the tightness of the intake connections, and the condition of the charge-air cooling components are also inspected. Intake leaks or improper turbocharger operation can reduce engine performance and, under certain conditions, increase the thermal load on the power unit.

The starter motor, alternator, and electrical auxiliary equipment are also inspected. These components affect the engine's ability to start correctly and the operation of the machine's electrical system. If any defects are identified, the scope of the repair is determined based on the inspection results. Once the work is complete, all components intended for reuse must be prepared for installation in a clean and serviceable condition.

### Assembling the John Deere 6068HF285 Engine

Once the inspection has been completed and the components prepared, engine assembly begins. This stage requires a high level of precision because even minor contamination of a working surface or an incorrectly set clearance can affect the service life of the power unit. All components must match the established engine configuration, and assembly must follow the appropriate technical procedures.

Before assembly begins, the block surfaces, oil passages, and component seating areas are inspected. The components are prepared in a way that minimises the risk of recontamination. The crankshaft and piston assembly is then installed, including the properly prepared pistons, piston rings, connecting rods, crankshaft, and bearings. Each component must be checked for correct seating and proper operating clearances.

During crankshaft installation, clearances and freedom of rotation are checked. Once the pistons and connecting rods have been installed, the mechanics verify that all components operate correctly and that no unwanted resistance is present. Bolted connections are tightened according to the appropriate procedures, taking into account the required tightening sequence and torque specifications. Clean oil passages are particularly important because residual contaminants can damage the bearings during the initial stages of engine operation.

The next stage is cylinder head installation. The mating surfaces must be properly prepared, and the gasket must be selected for the specific engine version. The cylinder head is installed according to the required procedure, and the valve train and timing components are assembled and checked for correct positioning. The components necessary for proper gas exchange and cylinder sealing are then inspected.

Once the main components have been assembled, the engine auxiliary equipment is installed. This includes the fuel, lubrication, cooling, and intake systems, as well as the turbocharger and electrical equipment if they were removed earlier. All hoses and connections must be clean, undamaged, and correctly matched. Particular attention is paid to oil lines, fuel lines, and charge-air hoses because leaks can lead to reduced performance or fluid loss.

Before the first start, the completeness of the assembly and the condition of all connections are checked. The lubrication system must be prepared according to the procedure applicable to the engine to minimise the risk of components operating without an adequate oil film. Fluid levels, auxiliary equipment mountings, and the conditions required for safe testing are also verified.

After assembly, the engine is prepared for starting and testing. The systems are checked for leaks, connections are verified, and the operation of components required for starting is confirmed. All these checks must be completed before the unit proceeds to the next stage. Careful assembly provides the foundation for reliable starting and subsequent operation in the Tesab 623CT mobile crusher.

### Post-Overhaul Engine Testing on an Engine Dynamometer

One of the most important stages of the John Deere 6068HF285 overhaul is testing the engine on an engine dynamometer. Testing the unit outside the machine makes it possible to assess its performance under controlled conditions and verify whether the work has achieved the expected results. This is particularly beneficial for engines powering mobile stone crushers because reinstalling them involves additional organisational work and downtime costs.

An engine dynamometer allows the engine to be loaded in a controlled manner rather than limiting the assessment to a brief start without load. During this test, the engine's behaviour under different operating conditions can be observed, and the stability of its basic parameters can be checked. Depending on the test equipment and the scope of the procedure, monitored parameters may include oil pressure, temperature, engine speed stability, and the engine's response to changes in load.

Before testing begins, the engine's readiness for operation, fluid levels, and the tightness of accessible connections are checked. The engine must be correctly connected to the test stand, and all systems required for safe operation must function properly. An initial test is then performed to assess starting, operational stability, and basic parameters. Any concerning symptoms must be investigated before proceeding to the next stage.

After the overhaul, the engine should undergo an initial running-in period at a low load. The procedure used by WIBAKO предусматриes at least 16 hours of operation under light conditions, at approximately 20–30% of the rated load. This stage allows the mating surfaces to bed in gradually and makes it possible to monitor the engine's behaviour after assembly. During this period, the basic parameters, operational stability, and any signs of leakage are checked.

Once the initial test has been completed successfully, the load can be increased gradually. The engine is tested repeatedly at higher load levels to assess its response and behaviour under different operating conditions. Monitoring includes oil pressure, temperature, and operational stability. If any irregularities occur, the test must be stopped and the cause identified before the engine is approved for further operation.

Dynamometer testing is particularly important for an engine operating in the Tesab 623CT crusher. During crushing, power demand can vary depending on the type and hardness of the material, the feeding method, and the load on the working system. The engine must therefore maintain the required parameters not only during starting but also throughout extended operating cycles. Load testing can reveal some problems that might remain undetected during a short idle test.

It is important to note that dynamometer testing does not replace all diagnostic procedures or the subsequent inspection of the engine in the machine. Its purpose is to verify the engine's operation under test-stand conditions and reduce the risk of reinstalling a faulty unit. A successful test, combined with a thorough mechanical inspection, is an important part of overhaul quality control.

Once testing is complete, the results and observations are analysed. For engines tested by WIBAKO, the documentation may include graphs of operating parameters such as oil pressure, power, and temperature under load. The scope of the documentation depends on the test performed and the measurements available. Reviewing the results helps assess the engine before it is reinstalled in the crusher and provides a reference point for subsequent maintenance.

### Reinstalling the Engine in the Tesab 623CT Crusher

After the overhaul and dynamometer tests have been completed successfully, the John Deere 6068HF285 engine can be prepared for reinstallation in the Tesab 623CT mobile crusher. Before transport, the unit and its connections are checked and secured to minimise the risk of contamination or damage. At the same time, the engine compartment must be prepared, and the condition of the components that will be reconnected to the overhauled engine must be verified.

Installation is carried out using a crane provided by the customer. Before lifting the unit, the mechanics check the mounting points and prepare the work area. The engine is gradually lowered into the compartment, maintaining the correct position relative to the brackets and other structural components. During this operation, impacts and excessive stress must be avoided to prevent damage to the housing, connections, or auxiliary equipment.

Once the engine is positioned, it is secured, and the correct seating is checked. The associated components are then connected, including the cooling, lubrication, fuel, and intake hoses, as well as the electrical wiring. All connections must match the configuration of the specific machine. If worn hoses, damaged clamps, or leaking connections were identified during the earlier inspection, they must be repaired or replaced before starting the engine.

Particular attention is paid to the intake system. Air hoses must be correctly fitted, and their connections must be airtight. Any leaks can affect boost pressure and reduce engine performance. Cooling hoses and oil connections are checked in the same way. Correct routing of the lines minimises the risk of abrasion, contact with hot components, and vibration-related damage during crusher operation.

Once the auxiliary equipment has been connected, the completeness of the installation is checked. Mountings, mechanical connections, hose condition, and accessible inspection points are examined. The engine is then prepared for its first start by checking fluid levels and performing the procedures required for safe operation. The initial start should take place under controlled conditions, with the engine ready to be shut down immediately if any irregularities occur.

After starting, the mechanics monitor oil pressure, temperature, engine speed stability, and overall engine behaviour. They also check the connections for leaks and look for any fluid loss. The inspection covers both the engine itself and the points where it connects to the crusher's systems. If all parameters are correct, further tests can be carried out under conditions suitable for safely verifying the machine's operation.

An important part of the process is checking the machine together with the operator. This makes it possible to assess the engine's performance in relation to the crusher's actual functions and confirm that the symptoms that originally prompted the repair have disappeared. The engine's response to changes in load and the correct operation of associated systems are verified. After the tests, accessible connections and potential leak points are checked again.

Successful test results provide the basis for completing the installation and returning the machine to service. The work performed should be properly documented, and the customer should receive recommendations regarding running-in, the first filter replacement, and subsequent inspections. For machines used in stone crushing, following the maintenance schedule is important for maintaining engine performance and reducing the risk of unplanned downtime.

### Post-Overhaul Engine Maintenance and the 50-Hour Inspection

Completing an overhaul and obtaining a satisfactory dynamometer test result does not mean that engine maintenance is finished. The first hours after restarting are important for assessing the engine's behaviour under actual operating conditions. In the Tesab 623CT crusher, attention should be paid to temperature changes, potential leaks, operational stability, and the correct functioning of associated systems.

WIBAKO recommends carrying out the first inspection after 50 operating hours from the restart of the overhauled engine. This inspection is performed by our service technicians. It is not limited to filter replacement. It also includes checking the connections between the engine and other components, inspecting auxiliary equipment, assessing sealing, and verifying the overall condition of the unit after its initial period of operation.

During the inspection, the mechanics check hose connections, mountings, accessible fuel and oil system connections, and cooling system components. They look for leaks and check whether hoses have become worn or loose. If any irregularities are found, corrective action can be taken early to prevent more serious damage.

After the first inspection, subsequent checks should be performed every 250 operating hours, but at least once every three months. The schedule should also take the manufacturer's recommendations and actual operating conditions into account. A machine used intensively for crushing mineral materials requires regular inspection because dust, vibration, and variable loads can affect the condition of hoses, connections, and auxiliary equipment.

Regular diesel engine maintenance helps identify signs of wear at an early stage and reduces the risk of serious failures. Proper post-overhaul servicing supports the durability of the repair and helps keep the Tesab 623CT crusher ready for operation.

### John Deere 6068HF285 Engine in Industrial Machinery

The John Deere 6068HF285 belongs to a family of industrial diesel engines with a displacement of 6.8 litres. It is a six-cylinder, turbocharged engine equipped with charge-air cooling. The specific power output depends on the engine version and application, so the unit must be identified using its identification plate and serial number when selecting parts or planning an overhaul.

John Deere industrial engines are used in a variety of applications requiring a reliable power source. However, when assessing whether a particular model is suitable for an application, the machine manufacturer's requirements, the configuration of associated systems, and the technical compatibility of the specific version must be considered. The engine family designation alone is not sufficient to confirm compatibility.

For machines such as the Tesab 623CT mobile crusher, correct matching of the power unit to the drive and working systems is particularly important. Selecting a replacement engine or parts for an overhaul must take into account the model designation, serial number, equipment configuration, and parameters required by the machine manufacturer.

### Summary of the Engine Overhaul in the Tesab 623CT Crusher

Overhauling the John Deere 6068HF285 engine in the Tesab 623CT mobile stone crusher requires a comprehensive approach covering diagnostics, removal, component inspection, mechanical repairs, auxiliary equipment checks, and careful assembly. Each stage affects the final result and must be carried out with consideration for the engine's specific design and its future operating conditions.

An important part of the process is testing the engine on a dynamometer before reinstalling it. Initial and load tests make it possible to assess the engine under controlled conditions, while the test documentation helps verify the work performed. This reduces the risk of installing an engine with problems that have not been detected beforehand.

WIBAKO provides diesel engine servicing and maintenance for construction and industrial machinery. Depending on the requirements, the work may include workshop repairs, engine removal and installation, and subsequent service inspections. A properly performed overhaul combined with regular maintenance helps reduce the risk of unplanned downtime and supports the continued operation of the equipment.

After restarting the Tesab 623CT crusher, an inspection is recommended after 50 operating hours, followed by checks every 250 operating hours or at least once every three months. Regular replacement of consumables and inspection of connections help keep the engine in good technical condition.

### John Deere Engine and Construction Machinery Service at WIBAKO

If the engine in a crusher, wheel loader, excavator, or other industrial machine loses power, consumes excessive oil, or exhibits concerning symptoms, it is worth starting with a thorough diagnostic assessment. Identifying the cause early makes it possible to determine the scope of the repair and avoid replacing serviceable components without technical justification.

WIBAKO provides engine and construction machinery services, including diagnostics, power unit overhauls, engine removal and installation, and dynamometer testing. Our mobile service team travels to customers throughout Poland, and removed engines can be transported to our workshop in Kojszówka. The scope of service is determined individually based on the machine type, engine designation, and identified faults.

When contacting us, it is helpful to provide the machine model, engine designation, and serial number. Additional information about the symptoms, repair history, and operating conditions helps us plan the diagnostic process. This makes it easier to determine the next steps and select a solution appropriate for the specific machine.

More information is available on our pages covering [diesel engine servicing and overhauls](https://wibako.com/serwis-silnikow-spalinowych), [mobile construction machinery service](https://wibako.com/serwis-mobilny), and [engine dynamometer testing](https://wibako.com/hamownia-silnikowa).

### Contact Us

Need diagnostics or an overhaul of the John Deere 6068HF285 engine in your Tesab 623CT crusher? WIBAKO provides comprehensive diesel engine repairs, engine removal and installation, and engine dynamometer testing. Contact us to discuss the scope of work and available service options.

[+48 33 870 42 00](tel:+48338704200) [biuro@wibako.pl](mailto:biuro@wibako.pl) [Formularz](https://wibako.com/contact)

Published: 2026-10-15

---

Source: https://wibako.com/about-us/news/894-repair-of-the-john-deere-6068hf285-engine-in-the-tesab-623ct-crusher
Contact: +48338704200, biuro@wibako.pl