When it comes to maintaining your Onan engine, one of the most important yet often overlooked components is the oil filter. The oil filter plays a crucial role in protecting the engine by removing contaminants from the oil that circulates through it.
In this guide, we’ll break down what to look for in an Onan engine oil filter, why regular replacement is necessary, and highlight five popular Onan oil filter options available online.
Onan Engine Oil Filter
1. Onan 122-0836 Oil Filter
- Type: Genuine OEM Onan replacement
- Compatibility: Widely used for Onan RV QG 4000, QG 5500, and Marquis Gold series
- Features: High-quality filtration media, durable metal canister, pressure relief valve
- Pros: Designed specifically for Onan engines, a perfect fit and performance
- Use Case: Best for users who want factory-grade parts without compromise
2. Fleetguard LF3707 Oil Filter
- Type: Cummins-authorized filter (Fleetguard brand)
- Compatibility: Fits many Onan RV and commercial generators
- Features: Advanced synthetic blend media, anti-drain back valve
- Pros: Manufactured by the Cummins company; high reliability
- Use Case: Ideal for long service intervals and high-performance expectations
3. WIX 51365 Spin-On Lube Filter
- Type: Premium aftermarket filter
- Compatibility: Fits many Onan models and cross-references with 122-0836
- Features: High-quality construction, excellent flow rate, metal end caps
- Pros: Affordable, trusted brand, effective filtration
- Use Case: Good choice for budget-conscious users wanting quality aftermarket options
4. Fram PH3614 Extra Guard Oil Filter
- Type: Aftermarket filter
- Compatibility: Cross-referenced with Onan 122-0836 and other part numbers
- Features: Engineered for conventional oil, 95% filtration efficiency at 20 microns
- Pros: Widely available, easy to install, economical
- Use Case: Ideal for routine generator maintenance without breaking the bank
5. K&N HP-1002 Performance Oil Filter
- Type: High-performance aftermarket filter
- Compatibility: Compatible with Onan 4000 and similar engines
- Features: Heavy-duty construction, high flow rate, 17mm exposed nut for easy removal
- Pros: Excellent for high-stress conditions, reusable with some cleaning systems
- Use Case: Perfect for frequent travelers or off-grid users who rely heavily on their generator
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Tips for Replacing Your Onan Oil Filter
Here are some best practices to follow during your next oil filter change:
- Warm up the engine slightly before draining the oil to ensure better flow.
- Use the right tools, such as an oil filter wrench, to avoid damaging the filter or housing.
- Apply fresh oil to the gasket of the new filter before installation for a tight seal.
- Do not overtighten. Follow torque specs or hand-tighten firmly and then add a ¾ turn.
- Check for leaks after installation by running the engine and inspecting the area.
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How Often Should You Replace an Onan Oil Filter?
The replacement frequency depends on your engine’s operating conditions and usage. As a general guideline:
- For light use (e.g., occasional RV trips): Replace the oil and filter every 100-150 hours or annually, whichever comes first.
- For heavy or continuous use (e.g., commercial or off-grid): Replace every 50-100 hours.
- Always refer to your Onan generator owner’s manual for exact intervals, as some models have specific recommendations.
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Choosing the Right Onan Oil Filter
There are genuine OEM Onan filters and a variety of aftermarket options that meet or exceed OEM specifications. While genuine filters offer guaranteed compatibility and performance, reputable aftermarket filters can provide similar performance at a lower cost.
Here are some key things to consider when choosing an oil filter for your Onan engine:
- Model compatibility: Match the filter to your generator’s model (e.g., Onan 5500, Onan 4000, etc.).
- Filter quality: Look for filters with durable construction, anti-drain back valves, and high filtration capacity.
- Micron rating: A lower micron rating indicates finer filtration. Aim for filters in the 20-30 micron range.
- Bypass valve: Ensure the filter has a bypass valve to maintain oil flow if it becomes clogged.
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Final words
The oil filter is a small but vital component of your Onan generator’s engine. Choosing the right one and replacing it regularly is essential for keeping your generator running reliably, whether you’re powering an RV, home, or job site.
While OEM filters are always a safe bet, many aftermarket options offer excellent performance and value.
Always cross-check the part number with your engine model to ensure compatibility. Investing in a quality oil filter is one of the simplest ways to extend the life of your Onan engine.
