John Deere S660 Problems

The John Deere S660 combine, a workhorse in fields across the globe, is known for its efficiency and advanced technology. However, like any complex piece of machinery, it's not immune to issues. Understanding the common problems that S660 owners and operators face can help you diagnose issues quickly, minimize downtime, and ultimately maximize your harvest. This article dives into the typical challenges encountered with the S660, offering insights and potential solutions to keep you rolling.

What Are the Biggest Headaches with the S660?

While the S660 is generally reliable, certain areas tend to cause more trouble than others. Let's break down some of the most frequently reported problems, focusing on the engine, threshing and separating components, cleaning system, and electronics.

Engine Issues: Powering Through, or Just Powerless?

The engine is the heart of any combine, and when it falters, everything grinds to a halt. S660s are typically equipped with a John Deere PowerTech engine, which are generally robust, but issues can still arise.

Fuel System Problems: Dirty fuel, clogged filters, and malfunctioning fuel injectors are common culprits. Symptoms include hard starting, rough idling, reduced power, and black smoke. Regularly changing fuel filters and using high-quality fuel are crucial preventative measures.
Cooling System Concerns: Overheating is a major concern, especially during hot harvest days. Leaks in the radiator, hoses, or water pump can lead to overheating. A faulty thermostat can also restrict coolant flow. Always ensure the cooling system is properly maintained and check coolant levels regularly.
Turbocharger Troubles: The turbocharger boosts engine power, but it's a complex component susceptible to failure. Oil leaks, unusual noises (whining or screeching), and a lack of power are signs of potential turbocharger issues. Proper lubrication and regular inspections are key to extending turbocharger life.
Sensor Failures: Modern engines rely heavily on sensors. Faulty sensors can lead to incorrect readings, causing the engine control unit (ECU) to miscalculate fuel delivery or ignition timing. This can result in poor performance or even engine shutdown. Diagnostic tools are necessary to pinpoint faulty sensors.

Threshing and Separating: Grain Loss Woes

The threshing and separating system is responsible for separating the grain from the plant material. Inefficiencies in this area can lead to significant grain loss, impacting your yield and profitability.

Rotor Issues: The S660 uses a single rotor for threshing and separating. Damage to the rotor bars, concaves, or cage can reduce its effectiveness. Regularly inspect these components for wear and tear and replace them as needed. Incorrect rotor speed settings can also contribute to grain loss.
Concave Problems: Concaves are positioned beneath the rotor and play a vital role in threshing. Worn or damaged concaves will not effectively separate the grain. Check the concaves for damage and proper adjustment. Ensure the concave clearance is appropriate for the crop being harvested.
Separator Grate Blockage: Material other than grain (MOG), such as stalks and leaves, can sometimes block the separator grates, reducing the separating efficiency. Adjusting the cleaning fan speed and pre-cleaner settings can help minimize MOG entering the separator.
Rotor Loss Monitoring: Keep a close eye on the loss monitors. High readings indicate that grain is being lost through the rotor or cleaning system. Investigate the cause immediately and adjust settings accordingly.

Cleaning System: Dirty Grain, Dirty Profit

The cleaning system removes remaining chaff and debris from the grain. A poorly functioning cleaning system results in dirty grain, which can be penalized at the elevator.

Chaffer and Sieve Adjustments: The chaffer and sieve are responsible for separating the clean grain from the remaining material. Incorrect settings can lead to excessive grain loss or dirty grain. Refer to the operator's manual for recommended settings for different crops and conditions.
Cleaning Fan Issues: The cleaning fan blows air through the chaffer and sieve to remove light material. A malfunctioning fan or incorrect fan speed can significantly impact cleaning efficiency. Ensure the fan is operating correctly and adjust the speed based on crop conditions.
Returns System Overload: The returns system sends unthreshed material back to the rotor for another pass. An overloaded returns system indicates that the threshing or separating system is not operating efficiently. Address the root cause of the overload, such as incorrect rotor speed or concave settings.
Material Buildup: Chaff and debris can accumulate in the cleaning system, reducing its effectiveness. Regularly clean the cleaning system to prevent buildup and maintain optimal performance.

Electrical and Electronic Glitches: The Digital Dilemma

Modern combines rely heavily on electronics for control and monitoring. Electrical and electronic glitches can be frustrating and difficult to diagnose.

Sensor Failures (Again!): As mentioned earlier, sensor failures can affect various systems, including the engine, threshing system, and cleaning system. Use diagnostic tools to identify and replace faulty sensors.
Wiring Harness Issues: Vibration and exposure to the elements can damage wiring harnesses, leading to intermittent problems. Inspect wiring harnesses for damage, corrosion, and loose connections.
Controller Malfunctions: The S660 uses various controllers to manage different functions. A malfunctioning controller can cause a wide range of problems. Diagnostic tools and specialized knowledge are often required to diagnose and repair controller issues.
Software Glitches: Software glitches can also cause problems. Ensure the combine's software is up to date with the latest version.
Display Problems: The in-cab display provides vital information. A malfunctioning display can make it difficult to monitor the combine's performance. Check the display's connections and consult a technician if the problem persists.

Specific S660 Model Year Problems: Are Some Years Worse Than Others?

While the core design of the S660 remained relatively consistent throughout its production run, some model years have been associated with specific issues. It's important to note that these are generalizations based on anecdotal evidence and reported problems, and not every machine will experience these issues.

Early Models (e.g., 2012-2014): Some early models experienced issues with the hydraulic system, particularly the header height control. There were also reports of excessive wear on certain bearings in the threshing and separating system.
Mid-Range Models (e.g., 2015-2017): While generally more refined, some mid-range models experienced issues with the electrical system, particularly the wiring harnesses and sensor connections. The fuel system also remained a common source of problems.
Later Models (e.g., 2018-2020): Later models saw improvements in reliability, but some owners reported issues with the software and display system. Also, the DEF (Diesel Exhaust Fluid) system can be problematic in any year, but it requires diligent maintenance.

Important Note: Regardless of the model year, proper maintenance and operation are crucial to minimizing problems.

Preventative Maintenance: An Ounce of Prevention is Worth a Pound of Grain

The best way to avoid S660 problems is to implement a comprehensive preventative maintenance program. This includes:

Regular Inspections: Conduct thorough inspections of all critical components before each harvest season and throughout the season.
Scheduled Servicing: Adhere to the recommended service intervals for oil changes, filter replacements, and other maintenance tasks.
Proper Lubrication: Ensure all lubrication points are properly greased according to the manufacturer's recommendations.
Cleanliness: Keep the combine clean to prevent material buildup and reduce the risk of overheating.
Software Updates: Keep the combine's software up to date with the latest version.
Operator Training: Ensure all operators are properly trained on the combine's operation and maintenance procedures.

Troubleshooting Tips: When Things Go Wrong

When problems do arise, follow these troubleshooting tips:

Consult the Operator's Manual: The operator's manual is a valuable resource for troubleshooting common problems.
Use Diagnostic Tools: Modern combines have sophisticated diagnostic systems that can help pinpoint the source of the problem.
Check the Basics: Before diving into complex repairs, check the basics, such as fuel levels, fluid levels, and electrical connections.
Document the Problem: Keep a record of the problem, including the symptoms, when it occurred, and any troubleshooting steps taken.
Seek Expert Help: If you are unable to diagnose or repair the problem yourself, seek help from a qualified technician.

Frequently Asked Questions

Why is my S660 losing grain over the back? Likely causes include incorrect rotor speed, concave settings, or sieve adjustments. Refer to the operator's manual for recommended settings.
What causes the engine to overheat? Potential causes include low coolant level, a faulty thermostat, a clogged radiator, or a malfunctioning water pump. Check these components and address any issues.
How often should I change the fuel filters? Fuel filters should be changed at the intervals recommended in the operator's manual, typically every 250-500 hours. Frequent filter changes are essential for preventing fuel system problems.
Why is my S660 throwing diagnostic codes? Diagnostic codes indicate a problem with one or more of the combine's systems. Use a diagnostic tool to read the codes and consult the operator's manual for troubleshooting information.
What is the best way to prevent electrical problems? Regularly inspect wiring harnesses for damage and corrosion. Ensure all electrical connections are clean and tight.

The Final Harvest

The John Deere S660 is a powerful and efficient combine, but it's not without its potential problems. By understanding the common issues, implementing a preventative maintenance program, and following troubleshooting tips, you can minimize downtime, maximize your yield, and keep your S660 running smoothly for years to come. Remember, investing in regular maintenance is far less costly than dealing with unexpected breakdowns during the crucial harvest season.