How Do I Remove Oil Separator Bar on Honda 175: Step-by-Step Guide
Maintaining your Honda GX160/GX200 or Honda 175 engine involves more than routine oil changes. One component that often gets overlooked is the oil separator bar, a crucial part of the crankcase ventilation system. Over time, this part can become clogged or damaged, affecting engine performance. In this guide, we walk you through how to remove the oil separator bar on a Honda 175 engine—safely and efficiently.
What Is the Oil Separator Bar and Why Remove It?
The oil separator bar is a narrow metal baffle located inside the valve cover or crankcase of small engines, like the Honda 175. It helps separate oil mist from blow-by gases before they exit through the PCV (positive crankcase ventilation) system.
Common Reasons to Remove It
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Oil leaks or seepage
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Excessive crankcase pressure
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Poor engine idling
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Cleaning or replacement during an overhaul
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Prepping the engine for racing or high-performance use
Tools You’ll Need
Before starting, gather the following tools and safety gear:
| Tool/Item | Purpose |
|---|---|
| 10mm socket and ratchet | Removing valve cover bolts |
| Gasket scraper or plastic putty knife | Cleaning mating surfaces |
| Torque wrench | Reassembling with correct torque |
| Shop towels | Wiping off oil and residue |
| Safety gloves and eyewear | Personal protection |
Step-by-Step Instructions to Remove Oil Separator Bar on Honda 175
Step 1: Prepare the Engine
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Turn off the engine and let it cool completely.
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Disconnect the spark plug wire to prevent accidental ignition.
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Remove any surrounding parts that may block access to the valve cover (e.g., air filter housing).
Step 2: Locate the Valve Cover
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The valve cover sits on top of the cylinder head, secured by four 10mm bolts.
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Use your ratchet and socket to remove these bolts.
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Gently pry off the valve cover. Be cautious not to damage the valve cover gasket.
Step 3: Identify the Oil Separator Bar
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Once the valve cover is off, locate the metal strip or bar that runs inside the valve cover or across the upper crankcase baffle area.
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It’s often secured by small bolts or press-fitted tabs.
Step 4: Remove the Oil Separator Bar
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Use a flathead screwdriver or a 10mm socket to loosen and remove the bolts securing the bar.
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If the bar is press-fit, carefully pry it up without warping the cover.
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Place the bar on a clean towel for inspection.
Cleaning and Inspection
Check for:
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Cracks or warping
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Built-up sludge or carbon deposits
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Blocked holes or vents
Clean the part using a degreaser and soft brush. If it’s damaged, replace it with a genuine Honda OEM separator bar.
Reassembly Tips
Step 1: Clean the Surfaces
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Scrape off old gasket material with a plastic scraper.
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Wipe surfaces clean with brake cleaner or alcohol.
Step 2: Reinstall the Separator Bar
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If reusing the old bar, make sure it’s fully dry.
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Bolt or press it back into place.
Step 3: Replace the Gasket
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Always use a new valve cover gasket to avoid leaks.
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Align the gasket and place the valve cover back.
Step 4: Torque the Bolts
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Tighten the valve cover bolts in a crisscross pattern to the specified torque: 7.2 lb-ft (9.8 Nm).
Engine Compatibility Table
| Engine Model | Oil Separator Compatibility | Gasket Part No. |
|---|---|---|
| Honda GX160 | Yes | 12391-ZE1-000 |
| Honda GX200 | Yes | 12391-ZL0-000 |
| Honda 175 | Yes | 12391-ZE2-505 |
Common Mistakes to Avoid
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Forgetting to disconnect the spark plug—a safety hazard.
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Overtightening bolts, which can crack the valve cover.
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Using old gaskets, which leads to leaks.
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Not cleaning mating surfaces, preventing proper sealing.
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Skipping inspection of the separator bar, risking future issues.
When Should You Replace the Oil Separator Bar?
Here are signs that warrant a replacement:
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Engine smoke from the crankcase breather
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Sludge buildup in the bar
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Excessive oil consumption
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Frequent stalling or backfiring
Replacing this part during routine maintenance or when installing a performance camshaft or piston upgrade is also advisable.
FAQ Section
How do I know if the oil separator is clogged?
If you’re seeing oil residue around the breather tube, or experiencing uneven engine performance, the separator might be clogged.
Can I run my engine without the oil separator bar?
Running without it can lead to excessive oil mist escaping, causing carbon buildup in the intake and reducing engine efficiency.
How long does it take to remove the oil separator bar?
The job can be done in 30–45 minutes with the right tools and experience.
Is it safe to clean and reuse the separator bar?
Yes, as long as it’s not bent, rusted, or damaged. Use engine-safe degreaser for cleaning.
Where can I get a replacement oil separator bar?
We recommend ordering from Honda-authorized dealers or reputable online platforms like Partzilla, Jack’s Small Engines, or Honda Engines Direct.
Conclusion
Removing and inspecting the oil separator bar on a Honda 175 is a straightforward yet essential task for maintaining optimal engine health. With the right tools, patience, and this guide, you can confidently keep your small engine running smoothly and efficiently for years.
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