Onan 2500 LP Generator Oil Change (Frequency, Type, Filter)

When you have moving parts, you always need some type of lubrication. For many parts simple grease will do. But for other parts where heat is an issue, then oil is the go-to lubricant. Changing the oil can be different on different devices and sometimes those differences are not much fun.

To change the oil filter on the Onan 2500 LP generator, model number 2.5 KVD-2089B, the most important information you need to be aware of is that this model does not require an oil filter. Also, if the generated is mounted to an RV wall, access may be restricted.

To learn more about how to change the oil in this generator model, just continue to read our article. It has the information you want to know about so you can perform this task without asking for help. Not every device needing oil comes with an easy oil change task.

Onan 2500 LP Generator Oil Change Frequency


Generators seem to be like semi-trucks. They go by hours and not mileage to do the maintenance work. In the case of this generator model, it is said, and we are going by the manual for this and other pieces of information, you should change the oil every month.

Or every 100 hours whichever is best for your generator use situation. Generators are not like passenger cars or trucks which can go a year or more without changing the oil. These delicate pieces of equipment need constant lubrication from clean oil.

When it comes to an Onan generator, the company would prefer that you use the best oil and they consider their own brand to be the best. The manual also states that you should check the oil level after every 8 hours of use or on a daily basis.

You should also check for oil, fuel, and exhaust leaks during those checks or at least fairly regularly.

Onan RV QG 2500 LP Oil Capacity


When your RV comes with this model of generator already installed, it is good news to hear that you do not need a lot of oil when it comes to doing an oil change. The oil tanks on these devices are not that large.

All you will need is one quart of 15W-40 oil, any brand will do, to complete the oil change. One thing we forgot to mention in the previous section is that this generator needs to have its oil changed after the first 20 hours of use.

This quick oil change is done to protect the device from metal shavings and other debris that may have remained inside after production. Included in the oil change is the recommendation that you also change the air filter and the spark plug (gap to .025”).

** We should note here that similar generator models may only hold 0.6 quarts of oil. So double-check before you fill the generator’s oil tank.

Onan 2500 LP Generator Oil Filter


One thing you should note about the model 2.5 KVD-2089B generator is that it does not require an oil filter. So check your owner’s manual for other 2500 LP generators to see if they require an oil filter or not.

You need to be forewarned that not all 2500 LP generators are the same. Some have the drain plug in different locations and if you read the wrong manual, you may get a bit confused when you do not find the drain plug.

Also, other LP models may have an oil filter so be careful and make sure you are reading the correct manual for your LP generator model. In watching a video on this task, no oil filter was mentioned for this device.

When you get ready to refill the oil tank, make sure the drain plug is back in securely and that you use 15W-40 viscosity oil. Onamax is the brand name that Cummins Onan created for their engines of all types.

If you live in colder regions of the country, it is okay to use different oil viscosity to protect your generator. The manual should tell you what those different options are and what temperatures they are best for.

Onan 2500 LP Generator Fuel Consumption


According to the manual we have in front of us, the fuel consumption is measured in 3 stages. For the no load stage, you can expect your generator to consume only 0.2 gallons per hour.

With a half load demand, the fuel consumption is registered at 0.21 gallons per hour. Then with a full load demand you can expect to see the generator consume 0.33 gallons per hour. These are all averages and your specific fuel consumption may vary.

Changing The Onan 2500 LP Generator’s Oil


These are just instructions for one mounted situation as it seems that different RVs have the generators mounted in different positions which can lead to some interesting work positions.

The first step would be to remove the dipstick. This will allow the air to push the oil out faster. The second step will be to remove the plug on the bottom of the generator.

As we said, similar models may have the drain plug in different positions. The plug may be a 14 mm size but have different sockets ready just in case it isn’t that size.

Once the oil has drained, put the plug back in and refill the tank, with up to a quart of oil. In some cases, you may not be able to reach the drain plug so you may need a suction pump to pump the oil out of the dipstick opening.

Some Additional Words

RV and generator makers do not make simple tasks as simple as they once were. One owner reported having to become a contortionist to do his oil change. This may be your experience.

But, however you do it, make sure to use the right oil viscosity and remember to replace the plug and dipstick securely. Also, make sure to read the correct manual for your generator.

Leave a Comment: