Onan 18-7875 Oil Filter Cross Reference: A Comprehensive Guide

Introduction

Maintaining your engine’s health is crucial, whether you’re powering a boat or an Onan generator. If you’re searching for an “Onan 18-7875 oil filter cross reference,” you might be wondering about compatible replacements.

The term likely refers to the Sierra 18-7875, a marine oil filter used in Ford-based engines and possibly some Onan generators. This guide explores its specifications, applications, and cross-references to help you find the right filter.

Sierra International is a trusted name in the marine industry, known for producing high-quality filters that meet or exceed OEM standards. The Sierra 18-7875 is designed for durability and performance in harsh marine environments.

This article provides detailed information on the Sierra 18-7875, including its specifications, compatible engines, and a comprehensive list of cross-referenced filters. Additionally, we’ll offer practical tips for choosing and installing the right filter to keep your equipment running smoothly. Let’s get started!

What is the Sierra 18-7875 Oil Filter?

The Sierra 18-7875 is a long canister oil filter engineered for Ford-based marine engines, particularly four and eight-cylinder models from brands like Mercruiser and OMC. Its high flow rate and excellent filtration make it a popular choice for boat owners. While primarily a marine filter, it may also be used in some Onan generators in marine or RV applications.

Key Specifications

The Sierra 18-7875 has specific dimensions and features that ensure compatibility with various engines. Here are its key specifications:

• Outer Diameter: 97 mm (approximately 3.82 inches)
• Height: 131 mm (approximately 5.16 inches)
• Thread Size: 3/4″ x 16 NPT
• Type: Long canister filter with anti-drainback valve

These specifications make the filter suitable for high-performance marine engines, ensuring efficient oil flow and contaminant removal. Always verify these dimensions when selecting a replacement to ensure a proper fit.

Applications

The Sierra 18-7875 is compatible with a range of marine engines, including:

• Ford 4-cylinder 2.3L engines
• Ford V-8 302 and 351 engines
• Mercruiser Stern Drive (part numbers 60565, 35-8M0116378)
• Mercury Marine (part numbers F724002, 56874, 35-802886Q)
• OMC Stern Drive (part numbers 502900, 173231)
• Yamaha Outboard (part numbers YSC-16231-20-0C, YSC-10231-20-0C)

While Onan generators typically use part numbers like 122-0836 or 122-0833, some models in marine settings may use Sierra filters like the 18-7875. Check your generator’s manual to confirm compatibility.

Onan 18-7875 oil filter cross reference

Finding a suitable replacement for the Sierra 18-7875 is essential when the original filter is unavailable or you’re seeking a cost-effective alternative. Below is a comprehensive list of Onan 18-7875 oil filter cross reference for the Sierra 18-7875, sourced from reliable marine parts suppliers:

Additionally, brands like AMRS offer filters (e.g., AMRS-18-7875) that replace Mercury Marine’s 35-802886Q, aligning with the Sierra 18-7875’s specifications. These cross-references are widely available from retailers like Amazon and Wholesale Marine.

Why Cross-References Are Important

Cross-references provide flexibility when sourcing replacement filters. For instance, if the Sierra 18-7875 is out of stock, you can opt for a Fram PH8A or Wix 51515, provided they match your engine’s requirements. However, always verify specifications to ensure compatibility and performance.

Additional Cross-Reference Sources

Marine parts catalogs, such as those from MarineEngine.com, confirm the Sierra 18-7875’s compatibility with multiple brands. These catalogs list additional part numbers, ensuring you have a wide range of options. Always cross-check with your engine’s manual for accuracy.

Is the Onan 18-7875 the Same as Sierra 18-7875?

The term “Onan 18-7875” may be a misnomer, as Onan generators typically use part numbers like 122-0836 or 122-0833. However, in marine or RV applications, some Onan generators may use Sierra filters, such as the 18-7875, due to shared engine designs with brands like Mercruiser. For example, Onan generators in boats may share components with Ford-based marine engines.

To confirm whether your Onan generator uses the Sierra 18-7875, consult your owner’s manual or contact Onan customer service. If your generator is used in a marine setting, it’s likely that the Onan 18-7875 oil filter cross references are compatible.

How to Choose the Right Oil Filter

Selecting the correct oil filter is critical for your engine’s longevity. Here are five essential tips to guide your decision:

1. Verify the Part Number: Ensure the filter’s part number matches your engine’s requirements. For example, if your engine uses a Sierra 18-7875, check for compatible cross-references.
2. Check Dimensions: Confirm the filter’s outer diameter, height, and thread size align with your engine’s oil filter housing.
3. Prioritize Filtration Efficiency: Choose filters with high-efficiency media to trap contaminants effectively, protecting your engine from wear.
4. Opt for Reputable Brands: Select filters from trusted manufacturers like Sierra, Fram, Wix, or Mallory, known for their quality and reliability.
5. Refer to Your Manual: Always consult your engine’s manual for the recommended oil filter part number and specifications.

By following these tips, you can ensure the filter you choose meets your engine’s needs and maintains optimal performance.

Installation Tips for Oil Filters

Proper installation of an oil filter is straightforward but requires attention to detail. Follow these steps to ensure a secure fit:

1. Clean the Mounting Area: Before installing the new filter, clean the oil filter housing to prevent dirt or debris from entering the engine.
2. Lubricate the Gasket: Apply a thin layer of clean engine oil to the filter’s rubber gasket to ensure a tight seal and ease removal later.
3. Hand-Tighten the Filter: Screw the filter on by hand until it’s snug, then give it an additional 3/4 to 1 turn. Avoid overtightening to prevent damage.
4. Inspect for Leaks: After starting the engine, check for oil leaks around the filter. If leaks occur, retighten or replace the filter as needed.

These steps ensure your filter is installed correctly, preventing oil leaks and ensuring proper engine lubrication.

Benefits of Regular Oil Filter Maintenance

Regularly changing your oil filter is essential for engine health. Here’s why:

• Removes Contaminants: Oil filters trap dirt, metal particles, and other impurities, preventing engine wear.
• Improves Performance: A clean filter ensures proper oil flow, maintaining engine efficiency.
• Extends Engine Life: Regular maintenance reduces stress on engine components, prolonging their lifespan.
• Prevents Costly Repairs: Replacing a filter is far cheaper than repairing a damaged engine due to poor filtration.

Sierra recommends changing oil filters every 100 hours of operation or annually, whichever comes first. Always follow your engine manufacturer’s guidelines for optimal maintenance.

Common Mistakes to Avoid

When replacing an oil filter, avoid these common pitfalls:

• Using an Incompatible Filter: Ensure the replacement matches your engine’s specifications to avoid leaks or poor performance.
• Overtightening the Filter: Excessive tightening can damage the filter or housing, making removal difficult.
• Ignoring Maintenance Schedules: Failing to replace the filter regularly can lead to clogged filters and engine damage.
• Not Checking for Leaks: Always inspect for leaks after installation to prevent oil loss and engine issues.

By avoiding these mistakes, you can ensure your engine remains in top condition.

FAQs

Is the Onan 18-7875 the same as Sierra 18-7875?

The term “Onan 18-7875” is likely a misnomer, as Onan generators typically use part numbers like 122-0836 or 122-0833. However, some Onan generators in marine or RV applications may use Sierra filters like the 18-7875. Check your generator’s manual or contact Onan customer service for confirmation.

Can I use a cross-reference filter instead of the original?

Yes, cross-reference filters like Fram PH8A or Wix 51515 can be used if they match the original’s specifications. Always verify dimensions, thread size, and filtration efficiency to ensure compatibility with your engine.

Where can I buy Sierra 18-7875 oil filters?

Sierra 18-7875 oil filters are available from marine supply stores, online retailers like Amazon and Walmart, and Sierra International distributors. Compare prices to find the best deal.

Conclusion

Navigating the world of Onan 18-7875 oil filter cross references can be daunting, but with the right information, it’s straightforward. The Sierra 18-787 “

5 oil filter, often referred to as the Onan 18-7875 in certain contexts, is a reliable choice for marine engines and possibly some Onan generators.

By understanding its Onan 18-7875 oil filter cross references, you can find suitable replacements to keep your engine running smoothly. Whether you’re maintaining a boat or a generator, this guide equips you with the knowledge to choose the right filter.