Keeping Your Generator Cool: Maintenance Tips for Summer

Sun shining at dusk on city skyline

We’ve given you our pointers for keeping your generator operating in cold weather, but if you’re in Texas like we are, you’re going to find you need maintenance tips for hot weather a lot more often. 

Safeguarding your standby or continuous generator during extreme heat is important not only for the life of the generator, but to guarantee that performance is not affected. 

At around 104 degrees fahrenheit, many diesel generators must be derated, or operated at a lower output level than their rated maximum; in other words, you’ll have to back off on your load.

Here are eight things you or your generator service company can do to keep your generator as cool as possible during the dog days of summer or any other heat waves. Always consult your generator manual for exact instructions if you choose to perform maintenance yourself.

1. Keep Bearings Lubricated

Insufficiently lubricated bearings can cause your generator to fail in the heat. While some generators with ball or roller-type bearings are outfitted with “lifetime” lubrication, sleeve bearings will usually have a reservoir with a sight gauge to check the oil level. A mineral oil-based lube may be used for high speeds and heavy loads, while grease is better for lower speeds and light loads.

2. Maintain Battery Health

Like a puddle on a hot sidewalk, hot weather can evaporate the electrolytes in your battery, which can cause it to give you start failures when the generator is called upon to run. 

Weekly visual checks of the fluid level should be done, and if the level has fallen below the top level of the separator, you should add enough distilled water to cover the plates. This should be done for each battery cell.

The terminal connections also need to be checked to ensure they’re tight, as loose connections can generate excess heat, which is the last thing you want in the summer! 

They may also need to be cleaned with a brass brush to remove oxides. After cleaning, apply protective grease or Vaseline to the joint and make sure the battery is clean and dry.

3. Clean the Filters

Hot, dry months mean dust (even from as far away as Africa at this time of year), and dust means clogged air filters and fuel filters, which mean more wear and tear on your diesel generator as it has to work harder to put out power. The air filter can be removed, knocked gently to get the dust off, and sprayed with compressed air to be cleaned, or it should be replaced if it has reached the end of its life.

Cleaning the fuel and oil filters are more complicated and probably best left to professionals, but they’re also important to keep your unit at optimal performance levels.

4. Monitor Potential Causes of Overheating

Keeping air filters clean is just one of a handful of ways to prevent the most common causes of overheating, which is all the more likely to occur in summer months because of the weather conditions. 

Other tasks you can do include:

  • Checking coolant levels and making sure there are no loose clamps or leaking gaskets, which are the most common failure sites for coolant hoses.
  • Keeping the unit’s exterior free from dirt and grease so that heat dissipates optimally.
  • Making sure you don’t have a broken fan, fan belt tightened improperly, collapsed coolant hose, or damaged exhaust.
  • Avoiding over-fueling or overloading the generator.

5. Support the Alternator

Alternators get hot; it’s just what they do. But dirt and heat can make them generate excess heat and reduce the ability for the windings to produce power. A visual inspection can reveal whether windings need to be cleaned to keep the alternator in good shape. 

If so, strip the alternator and blow it clean with either compressed air or, failing that, a leaf blower. Air is the preferred cleaner as any solvent or water sprayed in the alternator runs the risk of making its way into the bearings and ruining them. Blow air in from different angles and be prepared for nasty dust to come out.

6. Clear the Radiator of Oil and Debris

Having a clean radiator is crucial for keeping a genset cool in hot conditions. However, the gap of the radiator can get blocked by collected oil from blowby of the engine, dirt, dust, leaves, grass, insects, and other debris, hampering the efficiency of your unit. 

To avoid this problem, turn to your leaf blower or compressed air duster to clean that junk out.

7. Cool the Area Down

Keeping the ambient temperature around your generator as cool as possible can go a long way to reducing the maintenance work you have to do on the generator itself during the summer. 

Whether it’s keeping your genset in an air-conditioned room or setting up some kind of sun shade to keep a unit out of the direct sunlight, an ounce of heat prevention is worth a pound of cure. Even going so far as to move the generator to somewhere on the premises that can be kept cooler might be recommended in certain cases.

8. Ramp Your Testing Up

In most cases, it is recommended that non-mission critical generators are load-bank tested at 80% of their maximum load for 60 minutes at least once per year. Critical diesel generators could be tested much more frequently, but this wholly depends on individual requirements and industry regulations.

NFPA guidelines also state…

“Diesel generator sets in service shall be exercised at least once monthly, for a minimum of 30 minutes, using one of the following methods:

(1) Loading that maintains the minimum exhaust gas temperatures as recommended by the manufacturer

(2) Under operating temperature conditions and at not less than 30 percent of the EPS standby nameplate kW rating.”

– NFPA 110, Section 8.4.2

In the hotter months, consider switching to weekly exercising to ensure everything is working well. And either try to schedule your annual load bank test for the summer, or move to a biannual schedule, with one test in summer and one in winter.

Beat the Heat with Help from WPP

At Worldwide Power Products, we live in one of the hottest climates in the U.S., and we’re well-versed at keeping generators happy through summer heat.

Our maintenance services can keep your gensets tuned up so that they’re ready for the time of year when grid demand most threatens to overwhelm supply.