5679573 Crankcase Breather For Cummins 5417366 X15 XPI Engine ISX QSX

KOEED · Heavy-Duty Engine Components · Crankcase Ventilation · In stock

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What Is the 5679573 Crankcase Breather for Cummins?

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The 5679573 (cross-reference 5417366) Crankcase Breather is an OEM closed crankcase ventilation filter element engineered for Cummins ISX, QSX, and X15 XPI heavy-duty diesel engine platforms. Installed in the breather housing atop the valve cover, it separates oil mist from blow-by gases before the filtered air is recirculated into the turbocharger intake — a process known as closed crankcase ventilation (CCV). When the breather element becomes saturated or clogged, crankcase pressure rises, leading to oil pushed past turbo seals, weeping gaskets, and in severe cases, crankcase pressure forcing the dipstick out of its tube.

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In short: If you are servicing a Cummins ISX, QSX, or X15 engine and seeing elevated oil consumption, turbo inlet oil pooling, or seepage around the valve cover and front cover, the breather filter is the first low-cost item to inspect — and this is the OEM direct-fit replacement.

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Why the Crankcase Breather Matters on X15 / ISX Engines

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1. Filters Blow-By Without Restricting Flow

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What it means: Piston ring blow-by is a fact of life in any diesel engine. The breather element uses a coalescing media — typically a multi-layer fiber matrix — to trap oil droplets while allowing combustion gases to pass through to the intake.
Why it matters: If the media is restrictive or collapsed, crankcase pressure spikes. A healthy breather maintains near-atmospheric pressure in the crankcase at all engine speeds.
Result: Turbocharger oil seals stay intact, external gaskets stay dry, and the engine does not consume oil through the intake tract.

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2. Direct-Fit OEM Design — No Retrofit Needed

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What it means: The 5679573 element was engineered to the exact internal diameter, pleat count, and seal profile of the original Cummins breather housing. It drops into the factory CCV canister on the valve cover without adapters, modifications, or aftermarket spacer rings.
Why it matters: Aftermarket "will-fit" filters sometimes undersize the sealing lip by a fraction of a millimeter — just enough for unfiltered blow-by to bypass the element entirely.
Result: Confident, tool-free replacement that restores the CCV system to factory-spec filtration efficiency.

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3. Extended Service Interval When Replaced on Schedule

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What it means: Cummins recommends breather filter replacement at each major service interval (typically every 200,000 to 300,000 miles for on-highway, or 4,000-6,000 hours for industrial/off-highway engines). A fresh element handles the full service interval without restriction.
Why it matters: Fleet operators who extend the breather replacement interval beyond Cummins' recommendation risk progressive oil leaks that contaminate the charge air cooler, CAC piping, and turbo compressor wheel — repairs far more expensive than a scheduled breather change.
Result: Predictable maintenance cost per mile with no mid-interval failures when the replacement interval is followed.

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Key Specifications

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OEM Part Number	5679573
Cross-Reference / Alternate P/N	5417366
Brand	Cummins (OEM)
Compatible Engine Platforms	ISX (ISM/ISX family), QSX (industrial/marine), X15 XPI (Performance & Efficiency Series)
Component Type	Closed Crankcase Ventilation (CCV) Filter Element
Filtration Media	Multi-layer coalescing fiber (Verify exact media grade from Cummins datasheet)
Replacement Interval (Recommended)	Every 200,000-300,000 miles (on-highway); 4,000-6,000 hours (industrial/off-highway) — confirm per your engine's maintenance schedule
SKU	177988796165
Condition	New — OEM packaging

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Symptoms That Point to a Clogged Breather

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Before you throw a turbo or a head gasket at an oil-consumption problem, check for these telltale signs of a saturated CCV filter — any one suggests the breather is due for replacement:

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• Oil in the turbo compressor inlet or CAC pipes: unfiltered blow-by carries oil mist that condenses on the cold side of the turbo and pools in the charge air cooler.
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• Weeping valve cover gasket or front cover seal: pressure has to go somewhere. If the breather is plugged, it pushes past the weakest gasket interface.
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• Dipstick popping out under load: classic crankcase over-pressure symptom — the breather is fully saturated and crankcase pressure rises under boost.
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• Oil film around the breather housing itself: if the housing-to-element seal has degraded or the element is deformed, raw blow-by escapes right at the source.
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• Increased oil consumption with no external leak: oil is being ingested through the intake because the breather hasn't been changed on schedule.
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Typical Applications

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• On-Highway Heavy-Duty Trucks: Freightliner Cascadia, Kenworth T680/T880, Peterbilt 579/389, International ProStar/LT series with Cummins ISX or X15 power
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• Off-Highway Mining & Construction: Excavators, haul trucks, wheel loaders, and dozers powered by QSX industrial engines
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• Marine Propulsion & Auxiliary: Commercial vessels with QSX marine-rated engines requiring closed crankcase ventilation per EPA Tier regulations
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• Power Generation: Standby and prime-power generator sets built around the QSX platform
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• Fleet Maintenance Shops: Scheduled PM replacements across a mixed ISX/X15 truck fleet
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• Independent Diesel Repair: Overhaul and in-frame rebuilds where the breather is replaced as a standard consumable
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Frequently Asked Questions

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\"How do I know if my old breather is a 5679573 or a 5417366 — are they actually the same?\"

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Both numbers reference the same CCV filter element. Cummins has superseded the part number over production years — some engines left the factory with a 5417366-labeled element, while later service stock carries the 5679573 designation. The critical dimension (outer diameter of the sealing lip and the overall height that fits into the breather canister) is identical. If your engine dataplate calls for either number, this element fits.

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\"Does a clogged breather cause my turbo to fail, or is that an old mechanic's tale?\"

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It is not a tale — it is one of the most common root causes of turbocharger oil-seal failure on ISX engines. When the breather plugs, crankcase pressure back-feeds into the turbo drain tube (which relies on gravity and low pressure to return oil to the pan). Elevated pressure forces oil past the turbine-side and compressor-side seals, leading to blue smoke, high oil consumption, and eventually coke buildup on the turbine shaft. If you see oil in the compressor housing, change the breather first before condemning the turbo.

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\"Can I clean and reuse my old breather filter instead of replacing it?\"

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The coalescing media inside the 5679573 is not designed for cleaning. Once the fiber matrix is saturated with oil and carbon particles, its ability to separate aerosolized oil droplets from the gas stream is permanently degraded. Solvent washing or compressed-air blowout can collapse the media pleats, making the restriction worse than before. This is a replace-on-schedule consumable — do not attempt to clean it.

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\"I run an ISX in a high-idle application — do I need to change the breather more often?\"

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Yes. Engines that spend significant hours at idle (PTO operation, refrigeration units, stationary pumping) accumulate blow-by hours without corresponding odometer mileage. The breather sees continuous gas flow regardless of the odometer reading. For high-idle fleets or stationary applications, track the replacement interval by engine hours (approximately every 4,000 hours) rather than by miles. Confirm your specific interval from the engine's operation and maintenance manual.

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\"Can KOEED supply this breather in bulk for a fleet PM program?\"

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Absolutely. We work with fleet maintenance departments and independent service shops to supply recurring consumables — breather filters, oil filters, fuel filters — in bulk quantities with consolidated shipping. Send your annual forecast or a sample purchase order to Moritta@KOEED.COM and we will return a multi-unit quotation within 24 hours.

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koeed.com — Your Trusted PLC Supplier. Heavy-duty engine components, industrial automation parts, and fleet consumables. Worldwide shipping with 24-hour quote turnaround. All inquiries: Moritta@KOEED.COM.