11 Causes of Generator Overheating-[How to Safely Fix them?]

Not all generators in the market come with features like overload alarms, low-oil shutoffs, and overheat alarms to prevent potential hazards like generator overheating.

As an Energy and mechanical engineer, I can tell you that generators are crucial machines that ensure power continuity in various settings.

However, like any other machine, generators are prone to malfunctions that can significantly affect their efficiency and lifespan.

One of the most common problems that generators face is overheating, and it’s a problem that should not be ignored.

Generator overheating occurs when the temperature within the generator’s components rises beyond its recommended operating range. This can be caused by a variety of factors such as high ambient temperature, overloading, or insufficient cooling.

Overheating not only reduces the efficiency of the generator but can damage the internal components tools. In this article, we will explore in-depth the causes, symptoms, and remedies for generator overheating.

By the end, you’ll have a comprehensive understanding of generator overheating and the necessary steps to keep your generator running smoothly. So, let’s get started!

Is Generator Overheating Dangerous?

Generator Overheating

Overheating is a dangerous problem for generators because it can cause damage to the internal components, reduce efficiency, increase fuel consumption, and create safety hazards.

It can also cause the alternator to overheat which will damage the internal insulation.

Generators are designed to produce electrical power by converting mechanical energy into electrical energy, and this process generates heat as a byproduct. If the heat is not dissipated effectively, the generator can overheat, leading to several consequences.

Overheating can cause damage to the engine, alternator, and wiring of the generator, resulting in costly repairs, rapid maintenance, and poor longevity (How Long Does a Generator Last)

It can also reduce the efficiency of the generator, which can be problematic in critical situations, increase fuel consumption, and create safety hazards.

High temperatures can create a fire risk, and exhaust fumes can be hazardous to human health.

What are 11 Common Causes of Overheating?

1. High Ambient Temperature:

Generators have an optimum operating temperature range. If the temperature outside the generator exceeds this range, it can cause overheating which not only causes malfunctioning, but fire can hazard as well.

This is especially true for generators that are located in hot areas, such as a desert or directly under the sun.

2. Poor Ventilation:

The generator engine and alternator produce a significant amount of heat during operation.

If there’s no adequate ventilation or obstructed airflow around the generator, the heat cannot escape, leading to overheating.

The cooling system relies on proper ventilation, so it’s essential to ensure that the generator has enough space around it and that the ventilation system is working correctly.

Check out my article about how to safely run a generator in a garage. It provides a solution for the poor ventilation we are talking about.

3. Overloading:

As an expert on the subject, I can guarantee you that a generator has a maximum load capacity, and exceeding that capacity can cause the engine to work harder than it’s designed to do, leading to overheating.

In extreme cases, overloading can also damage the internal components of the generator, resulting in costly repairs. It’s essential to know the generator’s rated load capacity and ensure that the total load does not exceed this limit.

4. Low Oil Pressure:

The generator’s engine needs oil to lubricate its moving components and prevent internal friction. If the oil pressure is low, it can cause the engine to overheat and eventually shut down.

Low oil pressure can be caused by a malfunctioning oil pump or a lack of oil due to a leak or inadequate oil level.

5. Faulty Cooling System:

The cooling system of a generator plays a critical role in preventing overheating. The cooling system comprises several components, such as a radiator, coolant, water pump, and thermostat. If any of these components malfunction or fail, it can lead to engine overheating and damage.

6. Clogged Fuel Filters:

Fuel filters prevent contaminants, such as dirt, debris, and water, from entering the engine. If the fuel filters become clogged, it can restrict fresh fuel flow to the engine, leading to overheating.

7. Dirty Air Filters:

The air filter prevents dust and debris from entering the engine’s combustion chamber. If the air filter becomes dirty or clogged, it can restrict fresh airflow to reach the combustion chamber, leading to overheating.

8. Worn or Damaged Belts:

The belts on a generator transfer power from the engine to the alternator. If the belts become worn or damaged, they can slip or break, causing the generator to work harder and overheat.

9. Defective Thermostat:

The thermostat regulates the engine’s temperature by opening and closing the cooling system’s flow.

A defective thermostat can cause the engine to overheat or not reach its optimum operating temperature.

10. Poor Maintenance:

Proper maintenance is crucial for the smooth operation of generators. Neglecting maintenance tasks, such as oil changes, coolant flushes, and air filter replacements can cause various issues, including overheating.

It’s essential to follow the manufacturer’s recommended maintenance schedule and inspect the generator regularly to detect any issues early on.

11. Choke ON/CLOSED for A longer Time:

As the choke resists the airflow to the combustion chamber for an instant startup when the engine is cold.

If you forget to slide the choke to the RUN/OFF position after warming up the machine, the generator will not get sufficient intake of air, and as a result, the generator becomes overheated.

Recommended Read: How to Use a Generator Choke?

Can I Pour Water On My Generator to Cool It Down?

You should not splash water on an overheated generator. Doing so could cause electrical shock, damage to the generator, and even personal injury.

When a generator overheats, it’s typically because of a malfunctioning component or an overloaded electrical circuit.

In either case, adding water to the generator won’t solve the underlying problem. In fact, adding water could make things worse.

If water enters the electrical components of the generator, it could cause a short circuit, leading to more significant issues, such as fire or damage to the generator.

Instead of splashing water on an overheated generator, it’s best to turn off the generator and let it cool down naturally.

How to Prevent a Generator Overheating?

  1. Make sure you choose a generator that has a capacity that matches your power needs. If your generator is too small for your needs, it will have to work harder and generate more heat, which can cause it to overheat.
  2. Generators need a lot of ventilation to prevent overheating. Make sure your generator is placed in a well-ventilated area, and not enclosed in a small space like a closet or garage.
  3. It has been overheated. Leave it be. Don’t spray anything on it.
  4. Dirt and debris can accumulate on the generator and reduce its ability to cool down. Keep the generator clean by wiping it down regularly, and removing any debris that may have accumulated around the air intake and exhaust areas.
  5. Low oil levels can cause a generator to overheat. Make sure to check the oil level of your generator before each use and top it up if necessary.
  6. High-quality fuel burns cleaner and produces less heat than low-quality fuel. Use high-quality fuel to help reduce the risk of overheating.
  7. Overloading the generator can cause it to overheat. Make sure you know the capacity of your generator and don’t exceed it.
  8. If you’re using the generator in a hot environment, you can use a fan or other cooling aid to help keep it cool.
  9. If you’re using the generator for an extended period of time, take breaks to allow it to cool down. You can also reduce the load on the generator during these breaks.
  10. Some generators come with a temperature gauge that will tell you when the generator is getting too hot. Check the gauge regularly and take action if the temperature is getting too high.

How to Fix An Overheated Generator?

1. Shut Off The Generator:

When a generator overheats, it’s essential to turn it off immediately to prevent any damage to the internal components.

It’s important to note that the generator should be allowed to cool down before any further inspection or maintenance is performed.

2. Check The Oil Level:

Low oil levels are one of the biggest reasons for an overheated generator. The generator’s manual usually provides the recommended oil level, and it’s essential to ensure that the oil level is within this range.

If the oil level is low, add oil to the generator and check for any leaks. However, it’s important not to overfill the oil tank as this can also cause overheating.

3. Inspect The Air Filter:

A dirty or clogged air filter can cause the engine to overheat by restricting the airflow. It’s important to remove the air filter and check for any visible signs of dirt or damage.

If the air filter is dirty, it can be cleaned using compressed air or replaced entirely.

4. Check The Thermostat:

The thermostat in a generator regulates the engine’s temperature by controlling the flow of coolant.

If the thermostat is faulty, it can cause the engine to overheat by restricting the flow of coolant.

It’s important to check the thermostat and ensure that it’s functioning correctly. If the thermostat is faulty, it should be replaced.

5. Improve Ventilation:

Poor ventilation can cause the generator to overheat as it restricts the flow of cool air into the generator and the exhaust of hot air out of the generator. Its own exhaust heat will overheat the engine.

It’s important to ensure that the generator is placed in a well-ventilated area that allows for adequate air intake and exhaust. If necessary, install a fan to improve air circulation.

6. Clean The Cooling System:

The cooling system in a generator includes the radiator, water pump, and other components that help regulate the engine’s temperature. Over time, dirt and debris can accumulate in the cooling system, reducing its effectiveness.

It’s essential to clean the cooling system regularly to ensure that it’s working correctly.

7. Inspect Internal Components:

If the above steps do not fix the overheating issue, it’s important to inspect the generator’s internal components, such as the radiator and water pump, for any damage or malfunction.

It’s recommended to seek the help of a professional generator technician to inspect and fix any internal component issues.

Check out this engine overheating research to dig deep into the topic.

8. Use The Choke Wisely:

After warming up the machine, make sure to slide the choke to the OFF/RUN/OPEN position so that a proper lean air-to-fuel ratio should be fed to the generator for proper combustion.

Also, a sufficient intake of fresh air from the choke to the combustion chamber plays a vital role to cool down the engine.

Diesel Generator Overheating Causes

  • The coolant helps regulate the engine temperature, and low coolant levels can cause the engine to overheat. Check if the coolant levels are low or if it is leaked.
  • Coolant fans of diesel generators tend to break a lot. It is one of the biggest reasons for overheating.
  • The radiator helps dissipate the heat generated by the engine, and a dirty or clogged radiator can reduce its effectiveness. It’s important to clean the radiator regularly to ensure that it’s working correctly.
  • Damaged or clogged exhaust can also cause overheating.
  • Have you checked the oil levels? It is a massive reason for any type of generator.
  • Overloading the generator can cause it to overheat as it tries to produce more power than it’s designed to handle. It’s important to use the generator within its recommended capacity to avoid overloading.

How to Avoid Diesel Generator Overheating?

  1. Even if the property is enclosed, the airflow should never be restricted. Proper ventilation is a must.
  2. Use quality coolant and fuel.
  3. Regular maintenance is important. Timely change the oil filter and oil.
  4. Don’t push the generator beyond its limit. If it is rated 15000 watts, don’t even come close to 14600 or 14700 watts. Leave some space.
  5. Use a proper exhaust system for hot air buildup.

Frequently Asked Questions (FAQs)

How Do I Know If My Generator Has Overheated?

Overheated generators make loud noises, they emit a huge amount of heat through radiation, and you will notice unnatural vibrations and a burning smell. You may also see smoke, and backfiring  Your generator will also experience power surges.

 How Can I Stop Generator Overheating?

To prevent overheating, make sure you use the right-sized generator for your needs. Ensure the air filters are clean and not blocked. Also, place the generator in a well-ventilated area to allow for sufficient airflow. Regular maintenance and checking the oil and coolant levels can also help prevent overheating.

Can generator overheating cause a fire?

Yes, an overheated generator can be dangerous and even cause a fire. It’s important to take prompt action if you suspect your generator is overheating to avoid any potential danger.

Should I Try to Fix The Generator Overheating Myself?

Unless you have the required technical knowledge and experience, it’s best to seek professional help to avoid causing further damage or injury.



Kashif has been a valuable asset to the electric generator industry for over 5 years. Now, As a skilled energy engineer, he’s been on the front lines of diagnosing problems, fixing broken parts, and performing routine maintenance tasks to keep generators running smoothly.

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