Diesel Generator Oil Leakage: Causes and Solutions

As an important backup power device, diesel generators play a key role in many scenarios. However, the issue of diesel generator oil leaks troubles many users. Today, let us delve into the causes of diesel generator oil leaks and the corresponding solutions, helping everyone better maintain and care for diesel generators, extend their service life, and avoid safety hazards and economic losses caused by oil leaks.

As a backup power device, diesel generators play a key role in many scenarios. However, the issue of diesel generator oil leaks troubles many users. To better understand and solve this problem, we first need to explore the main causes of diesel generator oil leaks.

More than 80% of diesel generator oil leaks are caused by oil seal corrosion and aging. Most diesel generator oil seals are made of rubber, and rubber seals gradually lose their plasticizers under frequent alternating temperature changes. This can cause the seals to deform or even crack severely, leading to oil leaks. Just like human skin easily cracks in dry environments, rubber seals also become brittle under long-term temperature changes, losing their original sealing performance.

Some diesel generator manufacturers' process levels are substandard, which directly affects product quality. During production, if component machining precision is insufficient, or assembly is not performed strictly according to standards, it is easy to cause oil leaks during operation. In addition, poor maintenance and repair operation skills are also an important cause. If maintenance personnel are unprofessional and do not follow the correct methods during disassembly and assembly, it is easy to cause component damage or improper installation, resulting in oil leaks. For example, when removing the main bearing cover, if special tools are not used or bolts are not loosened in the correct order, the main bearing cover may deform, leading to oil leakage.

The quality of diesel generator components is also a key factor affecting oil leaks. If components have defects during production, such as sand holes or pores in castings, or if various gaskets, seals, and oil seals do not meet specifications, oil leaks are likely during operation. For example, a casting with sand holes is like a container with leaks and cannot effectively seal the oil. Additionally, if components are not properly protected during storage and transportation, and suffer bumps or scratches, their sealing performance will also be affected.

The operating environment and usage of a diesel generator also affect its sealing performance. If the equipment operates for long periods under low load or no load, the sealing effect of components such as the turbocharger's oil seals will decline, causing oil to enter the turbocharger chamber or even the cylinder with intake air. Long-term low-load operation also accelerates wear of moving parts and worsens the combustion environment, leading to early overhaul periods. In addition, excessive oil pressure can cause oil to seep from static joints. Just like a faucet, if the water pressure is too high, leaks occur.

After understanding the main causes of diesel generator oil leaks, the next step is to master how to inspect leak problems. So, how should diesel generator oil leaks be checked? Let's explore the inspection methods to prepare for resolving leak issues.

Engine oil is an important guarantee for the normal operation of a diesel generator. Therefore, first check whether the oil type, level, and quality meet the requirements. Different types of oil have different performance and applications. Using oil that does not meet specifications may cause poor engine lubrication, resulting in oil leaks. At the same time, insufficient or excessive oil will affect normal engine operation, and degraded oil quality may block oil passages, causing abnormal oil pressure and leading to oil leaks.

Whether the mating surfaces of diesel generator components are smooth and whether machining dimensions meet requirements is also an important aspect of leak inspection. If mating surfaces are uneven or dimensions are inaccurate, components cannot be properly sealed. For example, when installing the valve cover, excessive tightening can cause deformation and oil leaks. In this case, the leaking valve cover can be removed, carefully reshaped with a wooden stick to restore the contact surface, then a gasket can be placed and reinstalled.

Carefully inspect the sealing of various components, including gaskets, seals, and oil seals, to ensure they meet specifications and are properly installed. If damaged or non-compliant components are found, they should be replaced or repaired in time. For example, if the washer of a hollow bolt on a fuel line is uneven, remove and flatten it, then reinstall. If the problem persists, replace the washer or cut a thicker soft plastic material as a gasket. For leaks at the connection between a plastic fuel pipe and a metal joint, this is usually caused by hardening or cracking of the plastic pipe. Trim the hardened or cracked part, soften it with hot water, install it while hot, and secure it with metal wire.

The condition of the diesel generator's lubrication and cooling systems also affects sealing performance. If the lubrication system is blocked, it can cause abnormal oil pressure and lead to leaks. For example, the return hole in an air-cooled diesel engine's follower column is very important. If blocked, oil backflow is affected, causing leaks. At the same time, the cooling system's performance is critical. If engine temperature is too high or cooling efficiency is poor, components may deform or be damaged, leading to oil leaks.

From the previous analysis, we have identified the common causes of leaks and inspection methods. Next, let us explore how to effectively solve these oil leak problems, ensuring normal operation, extending service life, and avoiding safety hazards and economic losses.

The injector is a delicate component of a diesel generator. If dirty diesel is used or the machine has been in service for a long time, the injector is easily damaged, causing return oil. Since replacing injectors is costly, oil can be redirected through a return pipe back to the tank or into a diesel filter. If the return pipe is damaged, a plastic tube can be used to guide the oil into a spare container, filter it, and return it to the tank.

For fuel line leaks, corresponding solutions can be taken based on specific conditions. As mentioned above, leaks caused by uneven hollow bolt washers, leaks at plastic fuel pipe-metal joints, or metal fuel pipe cracks can be repaired by replacing washers, softening plastic pipes, or welding metal pipes. In addition, during fuel pipe installation, ensure proper bending, avoid forced installation, and prevent the pipe from touching the machine body to avoid wear.

If the valve cover leaks, remove it, carefully reshape it with a wooden stick to restore a flat contact surface, then install a gasket and reinstall. Pay attention to gasket quality and assembly requirements to avoid leaks caused by substandard or improperly installed gaskets.

To reduce the likelihood of diesel generator oil leaks, minimize low-load or idle operation. The minimum load should not be less than 25–30% of the generator's rated power. This ensures sealing performance of components such as turbochargers and prevents issues like oil entering undesired areas due to low-load operation. Also, regularly check oil pressure to prevent oil seepage at static joints caused by excessive pressure.

Sealant adhesives are an effective way to prevent oil leakage. They provide sealing, leak prevention, fastening, and gap filling. Follow the instructions carefully to ensure proper sealing.

Maintaining unobstructed oil circulation is a key measure to prevent leaks. Blocked oil circulation leads to abnormal pressure and oil leaks. Regularly check oil passages, remove debris and blockages, and ensure smooth oil flow.

To fundamentally reduce oil leaks, relying solely on post-issue inspections and repairs is insufficient. Daily maintenance and care are key to ensuring long-term stable operation.

Regularly Check and Replace Oil: Engine oil is the “blood” of a diesel generator. Regular checks and timely oil replacement are crucial. Follow usage and manufacturer-recommended intervals, and use the correct oil type to avoid low-quality oil.

Keep Equipment Clean: Keeping diesel generators clean not only improves appearance but also reduces oil leaks caused by dust and dirt. Regularly clean engine surfaces, especially around mating surfaces and seals, to prevent dirt accumulation and seal damage.

Regularly Inspect Components: Check seals, gaskets, oil seals, and other components, and replace damaged or aging parts. Also, ensure components are properly tightened to avoid leaks caused by looseness.

Operate Equipment Properly: Operate diesel generators according to instructions, avoiding prolonged low-load or idle operation. Monitor equipment status, and stop the generator to check if abnormal conditions occur, such as excessive oil pressure or high engine temperature, to prevent damage caused by improper operation.

Choose Appropriate Maintenance Services: If the diesel generator malfunctions or requires maintenance, choose professional services. Experienced technicians can accurately diagnose and repair faults, preventing damage or leaks caused by improper maintenance.

Oil leakage in diesel generators is a relatively common problem. By understanding its causes and adopting proper inspection and solution methods, oil leaks can be effectively prevented. At the same time, daily maintenance and care are also essential measures to prevent leaks. It is hoped that everyone will pay attention to diesel generator maintenance, promptly detect and resolve leaks, ensure normal operation, extend service life, and create more value for enterprises and individuals.