Tri-State Generator Alliance

Generator Service in Malvern

Generators Require Preventative Maintenance and Testing

Each manufacturer will have published maintenance for their generator system that must be followed. This maintenance is beyond just changing the oil. Here is an example of a good maintenance program with 2 site visits per year.

Inspection of general condition of engine for leaks, belt and hose condition, loose fasteners, brackets, etc.
Inspection of batteries and battery post; (clean if necessary), check electrolyte level and load test at 50%.
Inspect battery charger; check for proper operation and float voltage. Adjust as necessary.
Inspect charging alternator for proper operation.
Inspect cooling system, i.e. radiator, coolant level, coolant condition, water pump, pressure test, and proper louver operation.
Inspect generator starting aids for proper operation, i.e. coolant heaters, crankcase, battery heater, etc.
Inspect condition of exhaust system, i.e. muffler, exhaust flex, rain cap and condensate drain.
Inspect air filter; clean if necessary.
Inspect oil level; add if necessary.
Inspect engine protection devices and pre-alarms for proper operation, i.e. low oil pressure, over speed, over crank and high coolant temperature.
Inspect fuel systems, i.e. leaks, day tank operation, fuel levels.
Inspect brushes and slip rings, if applicable.
Inspect unit while running for satisfactory operating conditions.
Inspect generator output voltage, frequency and metering.
Inspect automatic transfer switch for proper operation, i.e. time delays, exercise timer, contacts and connections.
Advise proper maintenance procedures to maintenance personnel.
Written field service report, stating all services performed and description of any problems found.

In addition, one (1) inspection per year will include the following:

Oil change.
Oil filter change.
Fuel filter change, if applicable.
Lubricate generator bearing, fan shaft and governor linkage.Engine tune up to include replacing of spark plugs as needed.

Other Maintenance Considerations

Generators that are liquid cooled with radiators (like your car) will require a coolant service every 3 years or as needed.

Batteries typically last about 3 years and then replacement should be considered.

Commercial diesel generators often have a condition known as "wet stacking as they age" where un-burned fuel causes carbon deposits and impacts generator performance. Load Bank Testing can help clean out the system and burn off those deposits for commercial units. 


Commercial generators that are mission critical should be load bank tested. This is a specialized test that takes most of a day and is the only way to know if your generator is capable of performing to its design.