Generator Service and Preventive Maintenance Tips!

Planned maintenance can be defined as performing service, maintenance, inspections and testing on a generator set on a pre-determined schedule. Each maintenance program should include inspections for the status listed below:

  • Calendar Cycle Schedule – Depending on manufacturer recommendations and applications, cycles can be divided into weekly, monthly, quarterly, semi-annual and annual requirements.
  • Operating Inspections – Inspections to be performed on generator when operating. Critical operations can be monitored 100% of operating time. Non-critical operations can have basic checks performed as determined by application.
  • Layup – Generator are placed in layup when no longer in active use. Basic outline of steps for generator layup.

All planned maintenance charts define checks to be completed at a calendar interval. Coolant, lubricating oil and coolant levels can be at normal levels, but can be contaminated. When performing normal maintenance inspections look for the following:

  • Air Restriction Indicator – Indicates when air restriction to intake is greater than manufacturer specifications. Red in color means change air filter (scheduled or not). Generally indictor located on air filter housing. Can be reset after filter change.
  • Fuel Water Separator – This filter separates water from fuel contaminated with water. Water is routed to bottom bowl and can drain via valve. This can indicate main fuel source supply is contaminated.
  • Water Indicating Paste – Used to test main fuel supply. Spread on tank level stick. Pink in color with no water. Turns red when fuel is contaminated with water. Generally water at the lower section of tank.
  • Oil in Coolant – Oil floating on the coolant when cooling system is at ambient temperature. Can appear milky after engine operation. Engine lubricating oil leak into cooling system. Can be cylinder head gasket, defective engine block or cylinder head. Defect is where oil pressure is higher than coolant pressure.
  • Coolant in Oil – Oil has milky color on dipstick. Coolant leak into engine lubricating oil. Can be cylinder head gasket, defective engine block or cylinder head. Defect is where coolant pressure is higher than oil pressure.

Operating Inspections

The application the generator is used in defines the inspections that need to be performed while in operation. Each application requires development of a different inspection.
Always consult manufacturer’s guidelines when designing inspections to be performed when the generator is operating. Consider recent repairs and add into inspection criteria.


When an emergency generator is removed from service for a permeate period of time it is placed in the layup status. Some basic steps to place a generator in layup can include:

  • Disconnect generator batteries.
  • Drain fuel system and change fuel filters.
  • Drain coolant and change coolant filters.
  • Replace air filters.
  • Insure all intake and exhaust ports are covered.
  • Disconnect all generator supply connections.

If shipping the generator all DOT regulations must be followed. Industrial shrink wrapping is offered by many companies and offers long term storage options 

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