Routine oil and filter changes are one of the most important maintenance tasks for the Onan MDKBH marine diesel generator. Using the correct oil filter ensures proper oil flow, effective contaminant removal, and long engine life.
This guide provides a comprehensive Onan MDKBH oil filter cross-reference table, along with clear explanations to help you confidently choose the right replacement filter.
Onan MDKBH Oil Filter Cross Reference
| Onan OEM Part Number | Aftermarket Part Number | Manufacturer | Filter Type | Notes |
|---|---|---|---|---|
| 185-7444 | LF3925 | Fleetguard | Spin-On Oil Filter | Direct OEM replacement |
| 185-7444 | B1402 | Baldwin | Spin-On Oil Filter | Common heavy-duty equivalent |
| 185-7444 | 51365 | Wix | Spin-On Oil Filter | Matches OEM dimensions |
| 185-7444 | NAPA 1365 | NAPA Gold | Spin-On Oil Filter | Wix-based equivalent |
| 185-7444 | PH3387A | Fram | Spin-On Oil Filter | Widely available aftermarket option |
| 185-7444 | P550162 | Donaldson | Spin-On Oil Filter | Industrial-grade filtration |
| 185-7444 | SO1009 | Sakura | Spin-On Oil Filter | Used in marine applications |
| 185-7444 | L14670 | Mann-Filter | Spin-On Oil Filter | European aftermarket equivalent |
| 185-7444 | OC 266 | Mahle / Knecht | Spin-On Oil Filter | High-quality OEM-style filter |
| 185-7444 | Z145A | Hengst | Spin-On Oil Filter | Equivalent size and thread |
Notes
All listed filters are spin-on oil filters suitable for the MDKBH lubrication system.
Dimensions and thread specifications align with the OEM filter.
Availability may vary by region, but these part numbers are commonly used by marine technicians.
When possible, choose filters designed for diesel engines, as they typically provide stronger internal construction.
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Onan MDKBH Generator Overview
The Onan MDKBH is a compact marine diesel generator commonly found on boats and yachts. It is typically powered by a Kubota diesel engine, which uses a spin-on oil filter design. Because marine generators often operate under steady loads for long periods, oil cleanliness is critical.
Using the wrong filter can result in:
- Reduced oil pressure
- Poor filtration
- Increased engine wear
- Oil leaks due to an incorrect gasket fit
For this reason, only verified cross-reference filters should be used.
OEM Oil Filter for Onan MDKBH
The primary OEM oil filter specified for the Onan MDKBH is:
- Onan / Cummins Part Number: 185-7444
This filter is also used across several MDK-series generators, making it a common and well-documented part.
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Can You Use Aftermarket Filters on an Onan MDKBH?
Yes, aftermarket filters are safe to use as long as they meet OEM specifications. Many professional marine mechanics routinely use Fleetguard, Baldwin, Wix, or Donaldson filters without issue.
Key things to verify before installation:
- Correct thread size
- Proper gasket diameter
- Adequate bypass valve pressure
- Designed for diesel engine oil flow
If any of these are incorrect, the filter should not be used.
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Oil Filter Change Tips for Onan MDKBH
When replacing the oil filter on an Onan MDKBH generator, follow these best practices:
- Warm the engine slightly before draining oil to improve flow.
- Always remove the old gasket if it sticks to the mounting surface.
- Lightly oil the new filter gasket before installation.
- Hand-tighten the filter until snug, then tighten according to manufacturer instructions.
- Check for leaks after startup.
Replacing the oil filter at every oil change is strongly recommended.
How Often Should the Oil Filter Be Changed?
For most Onan MDKBH generators:
- Oil and filter changes are typically recommended every 100–150 operating hours, depending on usage and oil type.
- In harsh marine environments or high-load conditions, more frequent changes may be beneficial.
Always follow the service interval specified in the generator’s maintenance manual.
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Common Mistakes to Avoid
- Using a filter that “looks similar” but has a different thread
- Reusing old filters
- Overtightening the filter
- Installing automotive gasoline-engine filters not rated for diesel use
Avoiding these mistakes helps prevent oil pressure issues and seal failures.
Final Thoughts
The Onan MDKBH oil filter cross reference makes it much easier to service your generator without relying solely on OEM parts. While the original Onan 185-7444 filter remains the reference standard, high-quality aftermarket alternatives from trusted manufacturers provide excellent performance when matched correctly.
By using the expanded cross-reference table above and following proper installation practices, you can maintain reliable operation, extend engine life, and reduce maintenance costs without sacrificing protection.
