Onan 4000 Generator Oil Type and Capacity [Video] Troubleshooting

The Onan 4000 RV generator used 1.6 quarts of SAE30 or 15W-40 oil.
At low temps you can use 10W30 or 5w30.

You should change the oil every 100 hours or year.

You can do it yourself with:
t30 torx bit, 12mm socket.

Video clip how to change the oil:

Troubleshoot

1. Generator won’t start:

• Check the fuel level and ensure that there’s enough fuel in the tank.
• Inspect the fuel lines for leaks, cracks, or blockages.
• Make sure the generator’s battery is charged and the connections are clean and tight.
• Check the oil level and add oil if necessary, as low oil can prevent the generator from starting.
• Inspect the air filter and clean or replace it if it’s dirty or clogged.
• Check the spark plug for wear, damage, or fouling and replace it if necessary.

2. Generator runs but with poor performance:

• Ensure that the generator is not overloaded by turning off any unnecessary appliances.
• Check the fuel for contamination or water and drain and replace it if necessary.
• Inspect the fuel filter and replace it if it’s dirty or clogged.
• Clean or replace the air filter if it’s dirty or clogged.
• Inspect the spark plug and replace it if it’s worn or damaged.

3. Generator is unusually noisy:

• Check for loose components, such as the exhaust system or mounting brackets, and tighten them if necessary.
• Inspect the cooling system for obstructions or damage and clean or repair it as needed.
• Ensure that the generator is installed on a level surface to prevent vibrations.
• Check the internal components for wear or damage, which may require professional assistance.

4. Generator shuts down during operation:

• Ensure that the generator is not overloaded and turn off any unnecessary appliances.
• Check the oil level and add oil if necessary, as low oil can cause the generator to shut down.
• Inspect the cooling system for obstructions or damage and clean or repair it as needed.
• Check for any error codes or warning lights on the control panel and refer to the owner’s manual for specific troubleshooting guidance.

5. Generator produces no power or fluctuating power:

• Check the circuit breakers and reset them if they have tripped.
• Inspect the wiring and connections for damage or loose connections.
• Ensure that the generator is properly grounded.
• Check the voltage regulator and replace it if it’s damaged or faulty.

Cummins Onan generator specs:

4-cycle, OHV, single horizontal cylinder
max power at 60 hz, Gasoline – 8.3 bhp (6.2 kw)
air cooled
oil capacity 1.6 qt
Cylinder Crankcase: Aluminum alloy with iron
cylinder liner cast into the block, aluminum alloy oil base
Cylinder Head: Aluminum,valves in head
Fuel use: .7 Gallons per hour at full load

Detailed Specs

1. Rated Output: The Onan 4000 generator delivers a rated output of 4.0 kilowatts (kW) or 4000 watts, with a voltage rating of 120V AC. This power output makes it suitable for small to medium-sized RVs.
2. Engine: The generator features a single-cylinder, 4-stroke, air-cooled engine with an overhead valve (OHV) design. This engine is designed for durability and efficiency.
3. Fuel Consumption: Depending on the specific model, the Onan 4000 generator has a fuel consumption rate of around 0.5 to 0.7 gallons per hour at half load, which may vary based on the type of fuel used (gasoline, propane, or diesel).
4. Noise Level: With the MicroQuiet technology, the generator operates at a noise level of around 68 decibels (dB) at a 10-foot distance, making it compliant with the National Park Service sound level requirements.
5. Starting System: The Onan 4000 generator typically features an electric start system, allowing for easy and convenient starting with the push of a button or a remote switch.
6. Dimensions and Weight: The generator’s dimensions are approximately 30 inches in length, 19.7 inches in width, and 14.4 inches in height. The weight of the unit varies depending on the specific model but is typically around 172 to 190 pounds.
7. Control Panel: The control panel features various indicators and switches for easy monitoring and operation. Common indicators include an hour meter, a start/stop switch, and warning lights for oil pressure, temperature, and service alerts.
8. Safety Features: The Onan 4000 generator is equipped with various safety features, such as low oil shutdown, high-temperature shutdown, and overvoltage protection, ensuring safe and reliable operation.

Other models oil capacity.