How to Change Generator Oil?

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With regular maintenance, you can add years of use to your generator. Among other things, you should be changing the generator oil regularly to ensure optimal use. In this article, we’re going to discuss the process of changing the oil. Read on for a detailed explanation of all the steps and many tips and tricks we learned from years of generator use.

Before You Start

There are several things to think about before you start the process. First, make sure you have your owner’s manual nearby. This will tell you multiple things, such as the brand and model of your generator, where and how to check the oil, recommended oil type, and how often the oil should be changed.

You should also consider where you keep your generator and how often you use it because this will affect the maintenance requirements. If there have been 50-200 hours of use (depending on the model), the oil is due for a change. You can also use a dipstick and dip it in the oil for a check. If the oil is dirty, you can continue with the process.

Finally, make sure you have all the necessary tools before you start. You can replace the oil in under 10 minutes if you have everything you need. Here’s a list of everything you’ll need:

  • Protective gloves and goggles
  • Drain pan and a funnel
  • New oil filter
  • New oil
  • A clean towel/brush and a piece of cardboard
  • Oil filter wrench
  • Socket wrench (correct size)
  • Phillips and flat screwdriver
change oil in generator

How do I change the oil in my portable generator? Step by Step Guide

Now that you are sure your oil needs changing and that you have everything on our list, you can proceed. To safely change the oil, make sure you use protective gloves and goggles. The oil tends to be hot, and it’s also very dirty, so you don’t want it in your eyes or on your skin.

Step 1 – Warm the oil up

Oil tends to dense up when not in use, which makes draining a hassle. This is why you should turn on your generator for a few minutes to heat the oil and make it liquid again. Before the next step, turn your generator off, and you can wait for a couple of minutes again just so you don’t have to deal with scorching oil. It will still be hot though, so keep that in mind.

Step 2 – Get your generator on blocks

The goal here is to free the space under the oil drain plug. Put your portable generator on a couple of stable blocks and make sure they’re on an even surface. To make things easier, you can place the entire generator a bit higher so you don’t have to bend over.

Step 3 – Check the spark plug

This is another step that preserves your generator. Without the spark wire plugged in, the generator cannot start. You definitely don’t want to start it without oil inside, so this step is so important.

If you’re doing this for the first time, the owner’s manual is again your best friend. Consult it in order to locate the spark plug and to make sure you got all of them. Some more powerful models tend to have multiple spark plugs.

Once you locate it, you need to disconnect the spark wire by twisting and pulling it off the spark plug. Never pull the wire itself and after you unplug it, make sure it can’t come into contact with the plug again.

Step 4 – Prep for oil draining

Use the owner’s manual again (if necessary) to find the oil plug. It’s usually a hexagonal or square head, 3/8″ nut, but your manual will tell you exactly what to look for. Once you find it, make sure the area is clean of oil residue and debris so you can see what you’re doing. Wipe everything down and remove the oil fill cap to prep for the next step – draining.

Step 5 – Drain out the old oil

Make sure you have your oil pan underneath the oil drain and ready to catch every drop. Once the oil filler cap is off, you can remove the plug with a 3/8″ socket or a ratchet. Keep in mind that the engine oil will start draining out once you do this.

Collect the old oil into an empty canister or a container and make sure to do your eco part, and take it to a place that can recycle it. Google the nearest one to you and pay them a visit. This used oil is highly toxic and damaging to the environment and us, so don’t just throw it away in the trash can, or even worse, dump it into your yard.

Step 5 – Replace the filter

It is good practice to replace the oil filter every time you replace the oil. Although you can run fresh oil through the old filter, it simply doesn’t make much sense and will make your new oil dirty faster.

This is also a simple process. You’ll need an oil filter wrench or pliers to loosen it. You’ll be able to unscrew it manually once it’s loose. Some oil will start to drop, so you can place a container or a piece of cardboard below the filter and avoid the mess. Make sure you also take this oil to the nearest recycling center.

Ensure that the filter adapter looks good and clean, then proceed with putting on the new filter. Lightly lubricate the gasket with some oil and screw it on. Tighten it with a wrench, and you can move on to the next step.

Step 6 – Time for fresh oil

Now that the old oil is gone and everything is clean, you can finally proceed to put the new oil in. Screw the oil plug back on and take the cap if you haven’t already. Insert the funnel and start pouring. As for oil level, pour it until you start to see it reaching almost to the top of the plug. You can also check the manual for the recommended amount so you can be precise and sure you poured enough in.

Step 7 – Reconnect the spark wire

Lastly, you need to reattach and reconnect everything you disconnected to make the generator operational again. Put the cap back on the drain plug, and reconnect the spark plug wire. Start running it to let the fresh oil through the engine. Recheck the motor oil level, and add more if necessary.


Do you have to change the oil in a generator?

Yes, in order to run your generator properly and ensure years of use, dirty oil needs to be changed from time to time. Usually every 50-200 hours of use, depending on the frequency of use.

How often to change generator oil?

You should change the oil every 50-200 hours of use or regularly check with a dipstick to see whether an oil change is needed. Where you keep your generator and how much you use it will also influence how regularly you need an oil change.

What kind of oil does a generator use?

Consult the owner’s manual to determine which type of oil you should use. In general, you can use lower viscosity oil, which is thinner and better for colder climates, or higher viscosity oil, which is thicker and better for warm conditions.

How much oil does a generator take?

The correct amount of oil a generator takes will depend on its size and brand. On average, the amount ranges from 500 to 800ml.

Do generators have oil filters?

Yes, portable generators have oil filters which should be changed regularly. For best results, this means every time the engine oil is changed.

Final Thoughts

This entire process of changing oil may sound complex and includes multiple steps. But it’s really not that difficult. Once you get the hang of it, you’ll be able to change the oil of your generator in under 10 minutes. The key is to have all the necessary equipment, and you’re good to go!

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