Generac Oil Filter: Your Essential Guide to Selection, Change Intervals, and Troubleshooting​

Choosing the correct Generac oil filter and maintaining a proper replacement schedule is the single most important routine maintenance task you can perform to ensure the longevity and reliable operation of your home standby or portable generator. This comprehensive guide will provide you with all the necessary knowledge, from selecting the exact filter model for your generator to performing a change correctly and diagnosing common oil-related issues. Neglecting this simple component can lead to catastrophic engine failure, making informed care non-negotiable for responsible generator ownership.

​Understanding the Role of Your Generac Oil Filter​

The oil filter in your Generac generator has a critical, singular job: to remove contaminants from the engine oil. As your generator runs, microscopic particles of metal (from normal engine wear), carbon, sludge, and other debris circulate with the oil. If left unfiltered, these abrasives act like sandpaper on vital internal components such as bearings, camshafts, and cylinder walls. The oil filter traps these harmful particles, allowing clean oil to lubricate, cool, and protect the engine. A clogged or inefficient filter forces the engine to operate with dirty oil, drastically increasing wear. In extreme cases, a bypass valve opens to allow oil flow even when the filter is clogged, but this sends unfiltered, abrasive oil throughout the engine. Therefore, a quality filter changed at proper intervals is a cheap insurance policy against very expensive repairs.

​How to Select the Correct Generac Oil Filter​

You cannot use just any oil filter. Using the wrong filter can cause oil pressure problems, leaks, or insufficient filtration. Follow this step-by-step process to guarantee a correct match.

1. ​Consult Your Owner's Manual:​​ This is always the first and most authoritative source. The manual's maintenance section will list the specific part number(s) approved for your generator model and engine. Keep this manual in a safe, accessible place.

2. ​Identify Your Generator Model and Serial Number:​​ If the manual is lost, you can find the model and serial number on a decal attached to the generator. For standby units, it's typically on the side of the enclosure. For portables, it's on the frame. This information is the key to looking up parts. A common model format is "Guardian Series 22kW" or "GP6500."

3. ​Use Generac's Official Parts Lookup:​​ The most reliable method is to use the online parts portal on Generac's official website. Enter your model and serial number to navigate to the engine maintenance kit or filter section. This will display the precise factory part number.

4. ​Know the Common Generac Oil Filter Part Numbers:​​ Many Generac generators with their branded engines use a few common filters. However, ​never assume based on engine size alone. Always verify.

   • ​0J17070110S:​​ This is an extremely common filter used on many 16kW, 20kW, 22kW, and 24kW air-cooled Guardian Series home standby generators. It is a spin-on cartridge type.
   • ​0J17070107S:​​ Another frequent filter for many Generac portable generators and some older or smaller standby models.
   • ​070185C / 070185B:​​ Common for many newer Generac portable inverter generators.
   • ​0J17070121S:​​ Used on certain Evolution Series controllers and other models.
   • ​Important Note:​​ Generac also uses Enginuity and other branded engines. Some models, particularly larger liquid-cooled units, may use industry-standard filters from brands like Fleetguard (e.g., LF3000 series). Verification is critical.

5. ​Cross-References and Aftermarket Options:​​ The Generac part number will cross-reference to filters from major brands like Fram, Baldwin, Wix, and others. For example, a Fram PH3614 is a common cross for the 0J17070110S. Using a high-quality aftermarket filter from a reputable brand is perfectly acceptable and can be more readily available. Ensure the cross-reference is verified for your specific application.

​Recommended Oil Change and Filter Replacement Intervals​

Adhering to the factory maintenance schedule is paramount. Intervals are primarily based on run hours, not just calendar time. A standby generator that exercises weekly and experiences several power outages will need more frequent changes than one in a region with few outages.

• ​First Change (Break-In):​​ Most Generac standby generators require their first oil and filter change after the first ​25-30 hours​ of operation. This removes the initial metal wear particles from the engine break-in process. This is a crucial step often performed by the installing dealer.
• ​Subsequent Changes:​​ After the break-in change, the standard interval for air-cooled standby generators is every ​200 hours​ of operation or ​annually, whichever comes first. Even if the generator only runs for weekly exercise (approx. 20-30 hours per year), the oil should be changed yearly as it degrades over time.
• ​Portable Generators:​​ For portable models, follow the manual, but a common interval is every ​100-150 hours​ of use or at least once per season if used frequently.
• ​Severe Service:​​ If your generator runs for extended periods during frequent or long-duration outages, consider changing the oil more frequently, such as every 100-150 hours. Always check the oil level before and during extended run periods.

​Step-by-Step Guide to Changing Your Generac Oil Filter​

​Safety First: Always allow the generator to cool completely before starting. Disable the generator by setting the exercise switch to "OFF" and then disconnect the negative battery cable to prevent accidental starting.​​

​Tools & Materials Needed:​​ Correct new oil filter, correct type and amount of engine oil (typically 5W-30 synthetic for most models, but verify), drain pan, funnel, oil filter wrench (strap or cup type), rags, gloves, and a new washer for the drain plug if applicable.

1. ​Access the Filter:​​ On most standby generators, you open the main enclosure and then the smaller engine access panel. The filter is usually mounted vertically on the side of the engine block.
2. ​Prepare for Drainage:​​ Place the drain pan underneath the filter and oil drain plug area.
3. ​Remove the Old Filter:​​ Using an oil filter wrench, turn the filter counterclockwise to loosen it. Once loose, you can finish unscrewing it by hand. Be prepared for oil to spill from the filter and the filter mounting base. Tip the open end of the filter up as you remove it to minimize spillage. Allow all oil to drain into the pan.
4. ​Prepare the New Filter:​​ Wipe clean the filter mounting base on the engine. Take your new filter and lubricate the rubber gasket on its top with a thin film of fresh, clean engine oil. This ensures a proper seal and prevents the gasket from tearing during installation.
5. ​Install the New Filter:​​ Screw the new filter onto the mounting base by hand. Turn it clockwise until the gasket makes contact with the base, then tighten it an additional ​three-quarters to one full turn​ by hand only. Do not use the filter wrench for final tightening, as this can damage the gasket and cause a leak. The manufacturer's instructions on the filter box are the final authority.
6. ​Refill with Oil:​​ After also draining the engine oil via the drain plug (replacing the washer if needed), refill the engine with the exact type and quantity of oil specified in your manual. Use a funnel to avoid spills.
7. ​Check for Leaks and Reset:​​ Reconnect the battery cable. Start the generator and let it run for a minute. ​Carefully inspect around the filter base and drain plug for any signs of leakage.​​ Shut down the generator, wait a minute, and check the oil level on the dipstick, adding small amounts if necessary to bring it to the "Full" mark. Finally, reset the maintenance reminder light on the generator's controller if your model has one.

​Critical Troubleshooting for Oil Filter and System Issues​

• ​Oil Leak at the Filter Base:​​ This is the most common issue. Causes include: a double-gasket (the old filter's gasket stuck to the engine), a damaged or pinched new gasket, or a filter that is not tightened properly (either too loose or overtightened). ​Always ensure the old gasket is removed before installing the new filter.​​
• ​Low Oil Pressure Alarm/Warning:​​ If your generator displays a low oil pressure fault, a severely clogged oil filter can be a contributing cause, as it restricts flow. However, this warning is serious and more often indicates low oil level, wrong oil viscosity, a failing oil pump, or excessive engine wear. Check the oil level first. If correct, and after a recent filter change, ensure the correct filter was used. An incorrect filter with a faulty or missing anti-drain back valve can also cause low pressure on startup.
• ​Filter Canister is Dented or Damaged:​​ Never install a damaged filter. If the old filter is difficult to remove and gets crushed, ensure no debris falls into the open oil passage. A dent in the filter can collapse the internal pleats and severely restrict oil flow.
• ​Generator Won't Start After Oil Change:​​ Most Generac generators have a "Low Oil Pressure" shutdown switch. If the oil level is too high or too low, the sensor will prevent startup as a safety measure. Verify the oil level is exactly at the "Full" mark on the dipstick.

​Maintenance Tips and Best Practices​

• ​Use Synthetic Oil:​​ Generac recommends using a full-synthetic 5W-30 oil for most of its air-cooled engines. Synthetic oil provides superior protection across a wide temperature range, better resistance to breakdown during long run times, and improved startup lubrication.
• ​Keep Records:​​ Log the date, engine hours, oil type, and filter part number used for every maintenance event. This creates a valuable history for troubleshooting and helps ensure you stay on schedule.
• ​Buy Genuine or High-Quality Aftermarket:​​ While genuine Generac filters are guaranteed to match, premium aftermarket filters from brands like Wix, Baldwin, or Fram are excellent. Avoid no-name, cheap filters.
• ​Inspect the Old Filter:​​ When you remove the old filter, give it a visual inspection. Excessive metal particles or a "glittery" appearance in the drained oil can indicate abnormal engine wear and warrant further investigation.
• ​Have a Spare on Hand:​​ Especially before storm season, keep a spare oil filter and the correct oil in your supplies. After a major outage is precisely when you'll want to perform maintenance, and stores may be out of stock.

By understanding the importance of the Generac oil filter, selecting the right part, and performing timely changes with care, you directly invest in the reliable performance of your generator for years to come. This straightforward maintenance task is the cornerstone of preventing premature failure and ensuring your generator is ready when the power goes out.