Structured maintenance ensures genset reliability

Consulting engineers are in an excellent position to recommend structured maintenance programs to their clients.


Figure 1: In this photo, maintenance technicians are performing a test on a generator. Courtesy: Worldwide Power ProductsDiesel generators are used for on-site power generation and mission critical operations. They are also used for standby power in hospitals, airports, public safety complexes, and even nuclear power plants. In these locations, failure is not an option. However, many generator owners neglect a core component of genset reliability: maintenance.

Consulting engineers can do their clients a great service by encouraging them to incorporate formal, computer-aided generator maintenance programs into their projects at the outset and underscoring the importance of following them to the letter. Because it is difficult for companies with only one or two generators to maintain such programs in house, discussing generator maintenance services can also provide an opportunity for qualified consulting engineering firms to offer these services to their clients―or to partner with third-party vendors who specialize in this important process. 

Why maintenance is a problem

With generator maintenance, the old adage, “If it isn’t broken, don’t fix it,” comes to mind. Diesel generators in particular are such workhorses that it is easy for companies to let maintenance schedules slip or be reprioritized out of existence, especially in challenging economic times with reduced staffing levels. Generator operators with only one generator―or even a few―don’t have the personnel to assign a generator maintenance manager to oversee maintenance efforts, so the task is added to someone else’s already long list of duties, with inattention being a predictable result. 

Furthermore, companies with few generators may lack the technical skill to perform all maintenance routines correctly. For standby generators, which may be located in far-flung locations on a facility’s property, it’s often a simple case of out of sight, out of mind. Maintenance engineers have the best of intentions to get someone to crank the generator, perform fuel checks, and schedule necessary, periodic maintenance, but typically, it just doesn’t happen.

First step: automation

Although no one has come up with a way to automate generator maintenance itself, consulting engineers can recommend that their clients do the next best thing: automate the management process. Most companies have or are planning to use some type of enterprise asset management software/system (EAM) to keep tabs on their equipment. Generators are, after all, an asset that needs to be managed, and many times they can be incorporated into these systems. However, the EAM must support scheduling of events, and the company (or you, as their consultant) must establish a maintenance interval timeline with details on what operations should be performed during each event. 

The platform should also be able to generate advance alerts and work orders, as well as reminders that preferably cannot be overridden without management approval and will continue until the operation is marked as completed. It’s also beneficial if the system can send alerts and reminders directly to the phones and PCs of those responsible for doing the work. 

The platform should also support an interface that can contain the fields that correspond with interim-specific maintenance checklists (see “Genset maintenance basics link below”). The platform should be able to store historic data and then perform analyses to highlight unexpected fluctuations and out-of-range conditions that might point to impending failures. 

Depending on the client and chosen platform, these features may require custom coding particular to generators. For example, the equipment a construction company tracks might include backhoes, bulldozers, and excavators―all items that require routine maintenance. A hospital, on the other hand, may primarily be tracking electronic and electric equipment and nonpowered items that do not require such comprehensive, rigid maintenance schedules.

Best-practices generator maintenance intervals are as frequent as daily. For this reason, unless a previously implemented platform is sufficiently robust, a dedicated computerized maintenance management system (CMMS) or module, if the EAM supports one―may be a better course of action. 

Reporting and auditing

Checklists and reports are also vital components of the process. Companies (or their consulting engineers) should develop checklists that technicians can use in the field to indicate that items have been completed, and to record important measurements. 

If clients have the sophistication to give tablets to field technicians, you can help them integrate those devices with the chosen EAM or CMMS platform to allow digitized recording and uploading of data to the system. However, if the tablet’s interface does not support an interactive checklist that contains every process for each maintenance interval―and provide a place for measurements to be recorded―it must be backed by written documentation. 

Not only should the CMMS/EAM be able to accept all the data input by technicians during maintenance, but it should also be able generate reports that trained personnel can review to evaluate overall conditions. Furthermore, a management level individual should audit the maintenance program (preferably monthly) to confirm that maintenance operations were performed as tasked and that the resulting measurements have been properly entered into the system.

Figure 2: This graph shows the results of a typical resistive load test on a generator. Courtesy: Worldwide Power Products

This review is easy to accomplish if the platform can generate reports for management review. Historical reporting is the final piece in the puzzle. Optimally, the system should be able to analyze data and generate notifications of out-of-tolerance conditions. At the minimum, it must provide a detailed historical analysis that a human can interpret. 

Using third-party maintenance

It is strongly recommend that generator owners outsource at least their annual maintenance routines, unless they have qualified in-house technicians. Multi-generator operators for whom power is mission critical often outsource all their generator maintenance. 

Why do we recommend this? Third-party maintenance is third-party oversight. If operations slip through the cracks during the year, a reputable third-party provider will catch them during an annual inspection. The best vendors will also offer recommendations for parts that are nearing the end of their useful life and should be replaced to avert the possibility of sudden failure. 

If your clients appear totally befuddled at the thought of implementing a technological solution to track their maintenance program so rigorously, you may find an opportunity to sell them this service. Furthermore, you may wish to offer maintenance services to your clients (either developed in-house or outsourced to a partner). Just remember that your entire reputation―and possibly your clients’ business―is riding on maintenance being performed properly. If you choose to offer maintenance services or recommend other providers, perform due diligence to ensure the offering is up to the task. 

Genset maintenance basics


Performed properly, genset maintenance includes tasks that must be performed daily, weekly, monthly, quarterly, and annually. The following lists outline the minimal requirements for a prime (continuous operation) generator at various maintenance intervals. However, there are many peripheral operations that can be done to ensure optimal generator reliability and life. 

For standby and non-prime generators (not used continuously), load tests are also crucial for proper maintenance. Load test ensure the generator is tested and exercised to verify its reliability and ability to run at its full rated output. 


  • Inspection
  • Check coolant heater
  • Check coolant level
  • Check oil level
  • Check fuel level
  • Check charge-air piping 


  • Check battery charger
  • Check/clean air cleaner
  • Drain fuel filter
  • Drain water from fuel tank 


  • Check coolant concentration
  • Check drive belt tension
  • Drain exhaust condensate
  • Check starting batteries


  • Change oil and filter
  • Change coolant filter
  • Clean crankcase breather
  • Change air cleaner element
  • Check radiator hoses
  • Change fuel filters 


  • Clean cooling system
  • Perform other checks, based on monthly and quarterly schedules



It is difficult to quantify the importance of generator maintenance to clients. When something works as it should, owners may ascribe that fact to many reasons. The reality is that overlooked generator maintenance can and does cause failure. It is often responsible for thousands, if not tens of thousands, of dollars in unnecessary repairs and part replacements. In a worst-case scenario, poor maintenance can kill a generator engine, requiring a replacement or rebuild. 

To help prove your case to clients regarding maintenance, ask customers who use generators if they have a horror story to share. Undoubtedly you will find one or more. Use these stories (with the clients’ names excluded, if requested) to persuade every generator owner in your database to adopt best practices. It will be one of the greatest gifts you can give them, and it might result in a revenue bonus for your firm as well.

Spidle is vice president of Rental and Service at Worldwide Power Products in Houston, where he oversees the company’s rental fleet and service team. He has more than 18 years of experience in operations and management, specializing in developing and implementing operating procedures.

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