Generator Oil Change: How and When to Change Generator Oil
This article contains affiliate links. As an Amazon Associate I earn from qualifying purchases. Learn more.
Key Takeaways
- Do the first oil change early. The manuals we checked put it anywhere from 5 hours (Champion) to about 30 hours (Predator 3500).
- After that, most brands say every 100 hours or every 6 to 12 months. Westinghouse says 50 hours, and WEN says 25.
- Drain the oil while the engine is warm. Honda, Westinghouse and WEN all say warm oil drains faster and more completely.
- Generators drain in one of three ways: by tipping the oil out of the filler neck, through a drain bolt, or through a drain valve.
- None of the 10 portable generator manuals we checked mentions an oil filter, so a generator oil change is just oil.
A generator oil change is one of the easiest maintenance jobs you can do. It’s also one of the most important.
Generators are small air-cooled engines that often run for hours at a time. They hold very little oil, so that oil works hard.
We pulled the oil change steps and schedules from the owner’s manuals of Honda, Westinghouse, WEN, Firman, DuroMax, Champion and Briggs & Stratton generators.
This article shows you when to change generator oil and how to do it, whichever drain design your generator has.
How Often Should You Change Generator Oil?
Change it once after the break-in period, then on a regular schedule. Here’s what each manual says.
| Generator | First oil change | Then every |
|---|---|---|
| Honda EU2200i | 1 month or 20 hours | 6 months or 100 hours |
| Champion 8500W inverter | 5 hours | 100 hours or yearly |
| Briggs & Stratton P2200 | 10 hours | 6 months or 100 hours |
| DuroMax XP12000EH | 1 month or 8 hours | 6 months or 100 hours |
| Westinghouse WGen7500 | 1 month or 25 hours | 6 months or 50 hours |
| Firman P03615 | 25 hours | 100 hours |
| WEN 56380i | No separate break-in change | 25 hours |
Why the First Oil Change Comes So Early
A new engine’s moving parts are still wearing in. In the process, they shed tiny metal particles into the oil.
Briggs & Stratton explains that the break-in oil change removes those particles from the engine. Skipping it leaves them circulating.
When to Change Generator Oil Sooner
The intervals above assume normal use. Westinghouse and Firman both say to change the oil more often in dirty or dusty conditions, or in extremely hot weather.
Water or dirt in the oil is another reason. WEN and DuroMax say to drain the oil right away if it’s contaminated, even between scheduled changes.
Long outages add up fast, too. At 24 hours a day, a 100-hour interval passes in about four days.
Keep an Oil Change Log
Most portable generators don’t track hours for you. Write down the date and the approximate run time each time you change the oil.
Some manuals, like DuroMax’s, include a maintenance log page for exactly this. A note taped inside the cover works just as well.
Which Type of Oil Drain Does Your Generator Have?
Before you start, find out how your generator drains. The manuals we checked use three designs.
| Drain type | How it works | Examples |
|---|---|---|
| Tip drain | No drain plug. You remove the oil fill cap and tip the generator so the oil pours out of the filler neck. | Honda EU2200i |
| Drain bolt or plug | You remove a bolt at the bottom of the crankcase with a wrench. | Westinghouse WGen7500 (10 mm), DuroMax XP12000EH (12 mm) |
| Drain valve or hose | You open a valve, sometimes at the end of a hose, and the oil drains out. | WEN 56380i, Firman P03615 |
Your manual’s oil change section shows which one you have.
What You Need for a Generator Oil Change
- The right oil in the grade your manual lists. Most generators take 10W-30. See our generator oil article for each brand’s grade and capacity.
- A drain pan or a container that can hold the oil.
- A funnel, since generator fill openings are small.
- A wrench or screwdriver, depending on your model. You may need one for the maintenance cover and one for the drain bolt.
- Rags and gloves. Firman’s manual warns against prolonged skin contact with used motor oil.
- A sealed container to take the used oil for recycling.
How to Change Generator Oil
These steps follow the procedures in the manuals we checked. Your manual has the exact details for your model.
1. Run the Generator to Warm the Oil
Warm oil flows better. Honda says to drain while the engine is warm “to assure rapid and complete draining.” Westinghouse and WEN give the same advice.
Warm is not hot. Shut it off and let it sit a few minutes so you don’t get burned. Westinghouse says to let it cool for several minutes on a level surface.
2. Turn Off the Fuel
Honda says to switch the engine and the fuel cap vent to OFF to reduce the chance of a fuel leak.
WEN also recommends draining the carburetor before draining the oil, to avoid gasoline spills from the carburetor bowl.
3. Remove the Maintenance Cover
On most inverter generators, the oil fill sits behind a side panel. Loosen the screw or turn the knob and lift the cover off.
On many open-frame generators, the fill cap and drain are easy to reach without removing a panel.
4. Drain the Old Oil
How you drain depends on your generator’s design.
- Tip drain: Remove the oil fill cap. Tip the generator toward the filler neck and let the oil pour into your container.
- Drain bolt: Clean around the dipstick, then remove the bolt with a wrench. Westinghouse’s WGen7500 uses a 10 mm bolt, and DuroMax’s XP12000EH uses a 12 mm plug.
- Drain valve: Open the valve and let the oil run out. On Firman’s P03615, the end of the drain hose has to sit lower than the engine base for the oil to drain.
Let it drain completely. Then reinstall the bolt or close the valve.
5. Refill With Fresh Oil
Set the generator level. Pour in the oil slowly with a funnel, using the grade and amount your manual lists.
Small generators hold very little oil. The Honda EU2200i takes 14 ounces, and the WEN 56380i takes 18.6 ounces.
6. Check the Level
Each brand marks “full” a little differently, so follow your manual:
- Honda EU2200i: fill to the upper limit of the oil filler neck.
- Briggs & Stratton P2200: fill to the point of overflowing at the oil fill opening.
- WEN 56380i: fill until you see oil coming up the threads of the oil fill.
Don’t overfill. Briggs & Stratton and WEN both warn against it.
7. Close Everything Up
Reinstall the oil fill cap or dipstick, wipe up any spills, and put the maintenance cover back on. Then wash your hands.
8. Recycle the Used Oil
Pour the old oil into a sealed container and take it to a recycling center. Honda says never to put it in the trash, dump it on the ground or pour it down a drain.
The EPA suggests asking local auto shops, waste collectors or government waste offices where to drop it off. DuroMax suggests asking your local auto parts store.
Do Generators Have an Oil Filter?
Most portable generators don’t. None of the 10 portable generator manuals we checked mentions an oil filter.
That’s one reason regular oil changes matter so much. Without a filter, the only way to get rid of dirt and worn metal is to drain the oil.
If you own a permanently installed home standby generator, check its manual separately. Those are a different type of machine.
How Often Should You Check Generator Oil?
Check it before every use. Westinghouse says before each use or every 8 hours of running. Briggs & Stratton says every 8 hours or daily.
Checking matters even between oil changes. Generators hold so little oil that a small amount burned off can trip the low-oil shutdown.
Common Generator Oil Change Mistakes
- Skipping the break-in change. It’s the most important oil change your generator gets.
- Overfilling. With capacities under a quart, it’s easy to add too much.
- Checking the level on a slope. Always check on level ground.
- Using 2-stroke oil. Generators have 4-stroke engines and need 4-stroke oil.
- Going by the calendar alone during an outage. Count hours, not months, when the generator runs around the clock.
Tools That Make a Generator Oil Change Easier
You don’t need much. These tools match the steps above.
| Product | Why it fits | Where to buy |
|---|---|---|
| Lumax LX-1628 Drain Pan (6 qt) | Low profile, about 4 inches deep, so it fits under a generator’s drain bolt or valve. | Check price on Amazon |
| FloTool 10704 Measu-Funnel | Has an on/off spout and tube for small, hard-to-reach fill openings. | Check price on Amazon |
| Briggs & Stratton 5431K Oil Extractor (4 L) | A hand-pump extractor from an engine maker. Check that your manual allows this method before using it. | Check price on Amazon |
| Runleader RL-HM011F Hour Meter | An inductive hour meter with maintenance reminders, so you know when 50 or 100 hours have passed. | Check price on Amazon |
FAQs
How often should you change the oil in a generator?
After a short break-in period, usually 5 to 30 hours. Then most brands say every 100 hours or every 6 to 12 months.
Should you change generator oil hot or cold?
Warm. Honda, Westinghouse and WEN say warm oil drains faster and more completely. Let the engine cool for a few minutes first so you don’t get burned.
Do I need to change generator oil if I haven’t used it?
Many manuals use a time limit as well as hours, such as every 6 months. Change the oil at whichever comes first.
How much oil do I put in my generator after an oil change?
It depends on the model. Small inverters take about 13.5 to 20 ounces, and large generators about 1 to 1.2 quarts. Check our generator oil capacity table.
Conclusion
A generator oil change is quick and cheap. Do the first one after break-in, then every 100 hours or 6 months for most brands.
Drain the oil warm, refill to your manual’s mark, and recycle the old oil. Check the level before every use.
Not sure which oil to buy? Our generator oil article lists the grade and capacity for 13 popular models.
Storing your generator between outages? Fresh fuel matters as much as fresh oil. Read our article on ethanol-free gas for small engines.
Sources
- Honda. EU2200i owner’s manual, “Engine Oil Change.”
- Westinghouse. WGen7500 owner’s manual, “Engine Oil Change.”
- WEN. 56380i operator’s manual.
- Firman. P03615 operator’s manual, “Change Engine Oil.”
- DuroMax. XP12000EH manual, “Changing the Oil.”
- Champion Power Equipment. 8500W inverter operator’s manual.
- Briggs & Stratton. P2200 manual (Australian edition) and Engine maintenance schedule.
- U.S. EPA. Managing, reusing, and recycling used oil.