Onan Generator Oil Change

One of the cool things about owning an RV is having the ability to generate your own A/C power when you need it. So today I performed an oil change on my Onan MicroQuiet 4000 generator to keep it running in tip-top shape. The generator manual recommends changing the oil each year. Changing the oil is pretty straight forward and takes less than an hour. There is no oil filter on my model so that's one less thing to worry about. Some generator models do have an oil filter, so review the generator manual for your model before taking on this project.

Before starting I made sure I have the following things on-hand:

1. 2 quarts of SAE 30 motor oil. The generator takes 1.6 quarts. Oil recommendations vary depending upon the temperature ranges in your area. So be sure to check your manual.
2. Drain pan and funnel.
3. T-30 Torx socket for the Torx screws on the drain plug panel (got mine at Sears)
4. 9/16 socket for the drain plug.
5. Plumbers pipe thread sealant for sealing up the drain plug before you put it back in.

Changing the oil

The following procedure is pretty simple and outlined in your manual as well:

1. Run the generator for a few minutes to warm it up before you drain the oil.
2. Shut down the generator.
3. Remove the green panel on the underside of the generator that covers the drain plug (see photo). Use the T-30 Torx bit/socket to remove those screws. You only need to remove one screw then loosen the other. You can then just swing the panel off to the side.
4. Using the 9/16 socket, remove the drain plug.
5. Drain the oil into your oil pan until all of the oil is drained.
6. Apply some pipe thread sealant to the drain plug and screw it back in. Use a torque wrench if you have one to ensure you don't over tighten it. Check your manual for the recommended torque.

7. Remove the oil cover and add 1.6 quarts of new oil. Check your level to make sure you don't over fill.

That's it, you're done! Run the generator for a few minutes and check for leaks before screwing the drain plug panel back on.

Other things to check

Before I button up the generator, I take a few minutes to inspect the air filter, and wipe down visible areas. Finally, I log the date and generator hours in my RV maintenance log.

Performing regular oil changes is important to keeping your generator running efficiently for many years. I also run the generator for an hour each month with the A/C and water heater on. This keeps the generator components lubricated and makes starting easier.

Now let's go do some worry free boondocking!

Need more info?
(Update 9/11/2011)
Many of you have questions that I don't necessarily have answers to, so I've added some links here that may help:

• Cummins Support - Generator Operation Tips
• Cummins Onan RV Generator Handbook (PDF)
• RV.Net Forum Thread on synthetic vs Onamax oil in your Onan