Skip to main content
Nationwide Servicing
24 Hour Support Line: 03339 960 886

Diesel Generator Maintenance Guide

If you’re a business owner or facility manager, chances are you already understand the importance of having a reliable backup power source to ensure that your operations run smoothly in case of a power outage. Diesel generators are a popular choice for backup power due to their durability, efficiency, and availability of fuel.

However, like any other piece of equipment, diesel generators require regular maintenance to ensure their optimal performance and longevity. Vital Power’s team of engineers offers specialist generator service and maintenance right across the UK. In this blog, we’ll explore the importance of regular diesel generator maintenance and why it’s essential for your business or facility.

Diesel Generator Maintenance Checklist

There are a few steps you can take to ensure the smooth running of your generator in between regular service and maintenance from a professional.

Routine Inspection Schedule

It is advised to keep on top of visual inspections of your diesel generator. By doing this regularly you are less likely to miss any leaks or signs of corrosion and loose connections. Check the fuel lines, exhaust systems and filters for any blockages or damage.

Oil and Fluid Checks

Proper lubrication is essential for the smooth operation of the generator’s engine. Follow the manufacturer’s guidelines for fuel management. Regular oil changes help remove contaminants and ensure the engine components remain properly lubricated. Additionally, check the oil level frequently and top it up when necessary.

Air Filter Maintenance

Clean or replace the air filter following the manufacturer’s recommendations. Ensure that the air intake system remains unobstructed.

Fuel System Inspection

Inspect the fuel lines, connections, and filters for potential blockages or leaks. Ensure the fuel tank remains free from water and contaminants. Regularly run the generator under load to consume stored fuel, replacing it with fresh fuel.

Battery Maintenance

Maintaining the battery in a generator is crucial for ensuring reliable operation, especially during emergencies. Regularly inspect the battery for corrosion, loose connections, or physical damage. Measure the battery voltage to ascertain it remains within the recommended range. Test the battery’s starting capacity and charge it when necessary

Cooling System Checks

Monitor coolant levels and make necessary adjustments. Inspect hoses and connections for any signs of leakage. Maintain the radiator and intercooler surfaces to prevent overheating, ensuring the cooling fans operate effectively.

Common Issues and Troubleshooting

Regular Diesel Generator Maintenance

Generators are expensive bits of kit and it can be worrying when you feel there is an issue with your expensive equipment. There are some common issues such as leaks, low coolant or a dead battery which you can look out for.

Identifying Common Generator Problems

Low coolant levels in generators can lead to overheating and damage to engine components, which signals the need for prompt inspection and repair. Leaks, whether fuel, coolant, or oil, are common issues with generators and require regular maintenance checks to prevent them from getting worse. Fuel leaks often happen because of overfilling the tank or issues with the fuel pump system, so it’s best to have a professional handle refuelling. Coolant leaks typically occur in block heater hoses due to wear from high temperatures. Oil leaks, often mistaken for actual leakage, are usually caused by “wet stacking” in the exhaust system.

Insufficient fuel is a common cause of generator failure, so it’s important to regularly check fuel levels and promptly repair any leaks. Professional inspection is crucial for diagnosing and resolving issues like air in the fuel system or malfunctioning check valves. Starting problems in modern generators may be due to air entering the fuel system, so it’s wise to have a professional inspect for leaks or valve malfunctions.

Routine maintenance is essential for prolonging battery lifespan, and skilled technicians can swiftly address control panel issues. Block heaters, crucial for maintaining cooling system stability, may need replacement over time. By promptly addressing these common generator problems, you can ensure optimal performance and reliability.

Troubleshooting Steps for Performance Issues

If you feel like there are issues with your generator, there are some simple troubleshooting steps you can take to rule out any serious faults.

Inspect the Fuel Tank: The first step when your generator won’t start is to check the fuel tank. Ensure there’s an adequate amount of fuel. If levels are low or empty, refill with fresh gasoline, avoiding the use of old or stale fuel to prevent engine damage.

Monitor Oil Levels: Regularly checking and maintaining proper oil levels is crucial for engine performance and longevity. Use a dipstick to gauge oil levels on a flat surface and add recommended oil if levels are low.

Verify Start Switch Position: Check the generator’s start switch position. Ensure it’s set to “ON.” If not starting in the “ON” position, test for continuity using a multimeter. Replace the switch if it fails to register continuity.

Check Fuel Valve: Ensure the fuel valve and vacuum relief valve are open to allow gas flow from the tank to the carburettor. If fuel flow issues persist, inspect for clogs in the fuel line and filter.

By following these steps and conducting regular professional maintenance, you can troubleshoot and address common issues preventing your generator from starting efficiently.

Addressing Starting Problems

If your generator is failing to start, there are a few possible causes such as:

Stale Fuel: The presence of old or contaminated fuel can lead to starting difficulties.

Dirty Air Filter: A clogged air filter restricts airflow to the engine, hindering the starting process.

Spark Plug Issues: Fouled or damaged spark plugs can impede proper ignition, causing starting problems.

To troubleshoot these issues yourself you can try replacing the fuel. Drain the tank of old fuel and refill it with fresh, uncontaminated fuel. You can also clean or replace the air filter. Remove the air filter, clean it using compressed air or soapy water, and ensure it is thoroughly dry before reinstalling. If it’s damaged, opt for a replacement.

Inspect and clean or replace the spark plugs by removing them, cleaning them with a wire brush, and checking the electrode gap. If they’re worn out or damaged, replace them with new ones.

If you face complicated problems or lack the required expertise, it’s advisable to contact a professional to prevent additional damage and guarantee the safe operation of your generator. Regular maintenance and scheduled inspections will further extend the lifespan of your generator, ensuring it remains prepared to deliver dependable power when needed.

Best Practices for Generator Maintenance

Regular Diesel Generator Maintenance

Although scheduled maintenance from a professional should be planned and scheduled regularly, there are some maintenance steps you can take regularly to ensure the longevity of your generator.

Consistently inspecting your generator is the primary step in ensuring its dependable performance. Conduct visual checks for leaks, damages, and loose connections. Promptly addressing these issues can prevent more significant problems in the future. Equally crucial is cleaning the generator; pay particular attention to air filters and cooling systems. Blocked filters can obstruct airflow, leading to decreased efficiency and potential overheating.

Engine Oil and Fuel System: Maintaining the engine oil and fuel system is essential for smooth generator operation. Change the engine oil at regular intervals, following the manufacturer’s recommendations. Also, replace oil filters to prevent contaminants from impacting the engine’s performance. Additionally, regularly assess fuel quality and replace fuel filters to prevent sediment build up that could hinder fuel flow.

Battery Maintenance: The battery plays a crucial role in kick-starting the generator during power outages. Regularly test your generator’s batteries and promptly replace old or weak ones. Keep battery terminals clean and free from corrosion, as it can disrupt electrical connections and prevent the generator from starting.

Cooling System: Efficient cooling is vital to prevent generator overheating during operation. Regularly monitor coolant levels and top them up as necessary. Check for any signs of coolant leaks and ensure hoses are in good condition. Proper cooling safeguards the engine and other critical components from damage.

Electrical System: A well-maintained electrical system is essential for delivering stable power output. Verify the integrity of wiring and connections to prevent electrical issues that could disrupt power generation.

Safety Precautions During Maintenance

Even the most experienced engineers need to take caution when working with generators, so it is essential to be prepared if you are going to carry out any maintenance checks yourself to ensure your safety.

Before you attempt to refuel a generator, you will need to ensure the engine is completely cool. One reason is that the engine itself when hot could burn, but the main reason is that fuel is flammable and could cause an explosion if spilt on a hot engine surface.

If you do refuel your generator, it is key to store your fuel in a well-ventilated temperature-controlled space, away from heat sources and employee work spaces.

If you are carrying out maintenance on a generator that is placed in an area exposed to the elements, it’s best to avoid times when there are strong winds, heavy rain, or any other inclement weather. Although generators can be used in most conditions, heavy winds can cause debris to enter the generator and cause filter clogs. Heavy rain can cause damage to the internal components, it can also wet your hands which could cause electrocution.

Arguably the most important safety precaution you will need to take is to read and understand the manufacturer’s instructions. Different generators have different needs and setups, so it’s important to understand the generator you are working with.

Optimal Operating Conditions

Regular maintenance ensures optimal generator performance. Diesel generators require regular maintenance to function at their best. Over time, filters can become clogged, fuel injectors can become dirty, and batteries can become weak. These issues can cause the generator to operate inefficiently, resulting in increased fuel consumption and decreased power output. Regular maintenance ensures that your generator is functioning at peak performance, which maximises efficiency and minimises fuel costs.

Storage and Long-Term Maintenance Tips

If you want to ensure your generator has a long lifespan, maintenance is essential no matter if the generator is in regular use or held in storage.

Before you store a generator ensure the engine is cool to reduce engine temperature and prevent potential damage to the engine components. Once the engine is cool, it is recommended to check for leaks or damage in the fuel lines etc.

The storage area needs to be clean and dry and ideally not in direct sunlight, however, if you are storing indoors the area should be well-ventilated to avoid damp and prevent corrosion.

If the generator is not in use, it is still advisable to regularly inspect the condition. Check oil levels replace the filters where needed and check the battery. Although in storage the generator still needs to be run, as regular running helps to identify issues and keeps the components in working order.

By following these storage and maintenance tips, you can ensure your generator remains in optimal condition and ready for use when needed.

Send us a message

Discover diesel generator solutions for your commercial and public needs today

    Close Menu