How to winterize a generator

Did you know that generators require frequent and proper maintenance, especially in winter, so that they can run more efficiently?

As winter weather approaches, we tend to stay indoors and consume more electricity in our homes. We run lights, water heaters, appliances, and other electronic devices all day. This means our home's electrical system is more likely to be overloaded.

Strong winds, ice, snow, and sleet also pose a threat to power lines and electrical equipment. And when extreme weather hits, it becomes more difficult and dangerous for technicians to repair damaged equipment. When this happens, we can be without power for hours or even days.

Fall is the ideal time to winterize your generator before cold weather arrives. Winterizing lets you identify and fix small problems before low temperatures set in.

Importance of generator winterization

Winterizing will extend the life of your generator as we have to inspect every part of the generator and make some minor repairs to avoid bigger problems.  Left unaddressed, issues such as minor oil leaks tend to worsen over time, and accumulated debris around the unit can contribute to engine damage, both of which can shorten the equipment's overall lifespan. Improper storage practices can also introduce a fire risk, which is another reason a thorough seasonal inspection matters.

Plus, you'll get a longer run time because a clean carburetor, fresh fuel, and a good spark plug help the engine burn fuel properly.

You'll save a lot of money thanks to lower maintenance and fuel costs.

Your machine runs smoothly throughout the winter. No matter how harsh the winter is, your generator will provide you with uninterrupted operation.

Moreover, proper maintenance and clean fuel help the engine run more completely, reducing smoke and unburned-fuel emissions.

How to winterize a seasonal portable generator

You've used your generator to power your camping trip. Now is the time to store your RV and camping gear for the winter. Winterizing the generator before storing it will ensure it can wait for the next season to work again.

Drain the fuel line

While cold weather won't affect your generator much, you must drain the fuel lines and tank before storing. Gasoline left in the fuel system begins to degrade after about 30 days, forming gum and varnish that can clog the carburetor.

If storing longer than 30 days, drain the fuel tank and carburetor completely, remove the spark plug, and clean the carburetor to remove any accumulated sludge. Add about two tablespoons of engine oil into the cylinder through the spark plug hole, then pull the starter rope several times to coat the cylinder walls, and reinstall the spark plug. If you are storing the generator for less than 30 days, adding a fuel stabilizer is usually enough — a full drain is not required.

Change the oil and filter

Another task is to change the oil and filter. Fresh oil will keep parts lubricated in winter. Remember that oils have viscosity grades that meet specific temperatures. When changing your oil for winter, be sure to use an oil designed to work in cold and freezing temperatures.

Cold weather can change the viscosity of the oil, making it harder to flow. The low oil sensor may trigger shutdown. Make sure that you are using a winter-grade oil, which is thinner and flows more easily. Check your user manual for recommendations.

As a general guideline, 5W-30 oil is recommended for below-freezing temperatures, while 10W-30 or 5W-30 synthetic oil is generally used after the break-in period.

For LPG portable generator

If you run only LPG, fuel-system cleaning is unnecessary. Propane doesn't leave residue in the pipes because it burns cleaner. Disconnect the propane before storage. 

Keep in mind that propane pressure can drop in cold weather, which can reduce generator output or even cause the unit to fail to run, so this is worth checking before you rely on propane power in winter conditions.

Protect it from snow

Please do not leave your generator unprotected where ice and snow can damage it, as melting ice and snow can cause its components to rust and corrode. Your generator should be kept in a dry garage, shed, or another shelter. If this is not possible, place it on a tray or similar foundation to keep it above the waterline and cover it securely with a tarp.

How to winterize a standby generator

Standby generators are often placed near homes or businesses, with shrubs or gardens planted around them as camouflage. As the plants grow, they can overrun the generator and hinder the intake and flow of air.

Clear the peripheral brush

Cleaning out the generator area is advisable, as this will also provide clear access for maintenance. Dead leaves left near the generator can ignite and cause a fire. Keep the area around the generator clear — at least 3 feet of open space on all sides is a good rule of thumb for airflow and fire safety, but check your model's manual for the exact clearance it requires. Keep this space free of brush, leaves, and other debris at all times.

Schedule routine adjustments and cleaning

The next step is to ask a professional to make routine adjustments. A service technician will check all components, clean them, change fluids, and run them to diagnose any potential problems.

The technician will check the battery and auto-start feature. Cold weather is no friend of a battery, so we recommend checking its voltage regularly. If the battery is still low, it may be time to replace it before the cold weather begins.

Install the battery heater

Installing a battery heater is an additional method of preventing battery drain during cold weather and maintaining the ability to start the generator. When the temperature drops below a set threshold, the battery heater activates to prevent power loss. 

This matters because a lead-acid battery loses roughly 20% of its capacity at 0°C (32°F) and more than half at -18°C (0°F), making a reliable heater important for cold-weather starting. Many operators pair a battery heater with other warming components as part of a broader cold-weather preparation approach during cold weather, since skipping this kind of preparation can raise the risk of a failed start when temperatures drop.

Running regularly

Most standby generators are scheduled to start automatically and run for 15 minutes per month. If your generator lacks automatic scheduling, set a monthly test date and run the unit. When you need backup power, the parts are running and properly lubricated thanks to this routine testing.

How to winterize a year-round generator

When you use a portable generator, fuel and oil can get dirty and collect in the lines and carburetor. Engines need routine maintenance to be cleaned, lines checked, and parts replaced as necessary. If you didn't do it this season, winter is the time to get it done.

Following the recommended maintenance guidelines ensures that your generator will function properly throughout the winter.

If you have not had the unit serviced this year, ask a professional technician to perform the routine inspection described in the standby-generator section above. Consider using a winter fuel additive and switching to a winter-grade oil to help your generator run in the cold.

Make sure the battery is charged with a trickle charger and that the auto-start option is working if your generator has an electric start; check the battery voltage periodically and replace the battery if it stays low.

As mentioned, ice and snow can damage your generator. Generator guards are the best protection for generators from moisture that can cause corrosion of wiring and components. Check the exhaust outlet and cooling vents regularly to make sure snow and ice are not blocking them.

Check exhaust and vents

Remember that the engine of a generator needs airflow to operate efficiently. Exhaust vents can become blocked by ice or snow during winter. Regular visual inspections to remove any buildup will prevent problems. Water entering the exhaust pipe can cause hydro-lock, a condition that can render the engine useless, so it's important to keep exhaust openings clear. Exhaust outlets should be sloped toward the ground but kept in an elevated position to prevent water intrusion, which helps guard against ice buildup and moisture damage during the colder months.

Block heater

You might want to think about installing an engine block heater if you reside somewhere where temperatures may drop below zero for extended periods of time. This heater is also known as a water jacket heater. It helps with cold starts by keeping the engine and oil warm. Please note - not every engine block heater will work with every generator. Always check the manufacturer's recommendations for suitability.

Keep in mind that block heaters only maintain engine oil temperature while idle, so winter-grade oil is recommended if the generator will run continuously in sub-freezing conditions, as it reduces friction better than standard oil under those circumstances.

How to winterize a commercial diesel generator

Do a thorough inspection

Issues related to engine wear are often overlooked. But they can also cause a significant drop in the efficiency of diesel generators, especially in winter. So, do a thorough inspection of your generator.

Look for any obvious signs of wear or any other signs that may need repair or replacement. If there are any cracked hoses, loose wires, leaks, or other signs of deterioration, have them repaired immediately. Check the housing for cracks or openings caused by low temperatures and moisture, and address any issues before the next cold spell arrives. Also inspect the housing for dents or loose parts, and check wiring connections and the battery compartment for any signs of damage.

Clean or replace the oil filter

Commercial diesel generators need oil filters because they prevent trash, minute particles, and other pollutants from entering the engine.

If the filter is not clean or is old, particles can enter the engine and reduce performance. In extreme cases, it can also damage the engine's internal parts or other components, resulting in high repair costs.

Change the oil regularly

One of the most crucial components for a generator's efficient operation is engine oil because it lubricates every component of the engine that collaborates to generate power. This is even more important in winter when your generators work extra hard to generate electricity due to the weather and require more oil for better performance.

Oil degrades over time, so change it before winter to prevent engine damage.

Taking care of the diesel fuel system

Before you store your commercial diesel generator for the winter, be sure to fill up the tank and carry the fuel system stabilizer with you.

This stabilizer goes directly into the fuel tank and helps maintain fuel quality and reduce fuel evaporation until the generator is ready for use. A fuel stabilizer prevents fuel from degrading in cold conditions and should be added before storage. But to give the fuel stabilizer enough time to reach the entire system, run the engine for 5-10 minutes after adding it.

Test it before storing

One of the simplest methods to ensure that your system performs as planned is to test it. Run the generator for 30 minutes while keeping a tight eye on its operation. Check all parts for good performance, check for leaks, loose joints, etc.

If there are any signs of damage, you'll have time to repair it before finally putting the generator in storage for winter use.

Take the opinion from the expert

Before storing your diesel generator for the winter, have it checked and serviced by a qualified technician.

Minor problems in the engine, exhaust, or cooling system are hard to spot yourself, and they can quickly turn into major failures. An expert can identify issues early — while there is still time to repair them — keeping the engine efficient and extending its working life.

Conclusion

Although winterization prevents many cold-weather problems, freezing conditions can still cause issues. Many early-stage issues can be prevented with regular maintenance and periodic operation. Remember, fresh fuel, winter-grade oil, and premium batteries will give you a better chance of success when you have a power outage.

Always refer to the generator owner's manual for any winter recommendations. There is no one-size-fits-all method to winterize your generator because each make and model is unique.

FAQs

Are there any safety tips to follow when winterizing generators?

Operating the generator safely is critical. Proper ventilation for generators is critical. Second, carbon monoxide is a harmful gas that generators can produce, so install a carbon monoxide alarm. Finally, avoid using the generator in moist locations since this could result in a fatal electric shock.

Can I leave gasoline in my generator in winter?

Not for long-term storage. Gasoline starts to degrade after about 30 days, forming gum and varnish that can clog the carburetor. If the generator will sit unused for more than a month, drain the fuel system or add a fuel stabilizer and run the engine briefly to circulate it.

How can I keep my generator warm in winter?

In order to heat your generator in the real winter, you must operate it regularly and use the battery heater and engine block heater.

Will portable generators freeze in winter?

Your portable generator's engine oil may freeze like a gel in the harsh winter.

Can the generator be placed outside in winter?

Yes, if you have a suitable shelter or generator box without any space for snow or water. If your shelter or generator box has room for water and snow, your generator will be ruined