904-7904 Crankcase Ventilation Filter for Cummins ISX 11.9L Diesel
The 904-7904 Crankcase Ventilation (CV) Filter — also known as the engine breather filter — is a critical maintenance component for Cummins ISX 11.9L diesel engines found in Kenworth T680, T800, T880, W900 and Peterbilt 365, 567 heavy-duty trucks. This filter separates oil mist from crankcase blow-by gases before they're recirculated into the intake system. A clogged or degraded CV filter causes excessive crankcase pressure, oil leaks from seals and gaskets, and increased oil consumption — all of which lead to expensive engine repairs. iFJF's replacement is manufactured to IATF 16949 quality standards, delivering OEM-equivalent filtration efficiency at a fraction of dealer pricing.
Compatibility — Will This Fit Your Truck?
Engine
Make
Model
Notes
Cummins ISX 11.9L
Kenworth
T680
All model years
Cummins ISX 11.9L
Kenworth
T800
All model years
Cummins ISX 11.9L
Kenworth
T880
All model years
Cummins ISX 11.9L
Kenworth
W900
All model years
Cummins ISX 11.9L
Peterbilt
365
All model years
Cummins ISX 11.9L
Peterbilt
567
All model years
⚠️ Important: This filter is designed exclusively for the Cummins ISX 11.9L engine. It does NOT fit ISX 15L, ISX12, or Cummins X15 engines. If your truck has a different engine, please verify part number compatibility before ordering.
Specifications
Specification
Detail
Part Number
904-7904
OE Cross-Reference
3685528, CV50617, CV50634
Filter Type
Crankcase Ventilation / Engine Breather
Filtration Media
High-efficiency synthetic fiber
Material
Heavy-duty composite housing with nitrile seals
Certification
IATF 16949 (Automotive Quality Management)
Package Includes
1 × 904-7904 CV Filter Element
Key Features
OEM-Equivalent Filtration: Engineered to meet or exceed Cummins OEM specifications for particle separation efficiency. Captures oil mist and soot particulates before they foul the turbocharger, intercooler, and intake tract.
Heavy-Duty Construction: High-temperature composite housing resists warping under sustained boost and exhaust heat cycles. Nitrile rubber seals maintain elasticity across -40°F to 250°F operating range.
Direct Drop-In Replacement: No modifications, adapters, or special tools required. Remove old filter housing cap, swap the filter element, and reinstall. Average shop time: 10-15 minutes.
Extended Service Life: Designed for Cummins-recommended 150,000-mile CV filter replacement intervals under normal highway operation. Replace sooner (100,000 miles) in high-idle, severe-duty, or dusty environment applications.
Prevents Costly Failures: A neglected CV filter leads to crankcase over-pressurization — the #1 cause of rear main seal, front crank seal, and oil pan gasket leaks on ISX engines. A $40 filter beats a $3,000 seal replacement.
Why Choose iFJF for Your Cummins ISX CV Filter?
At iFJF Direct, we specialize in diesel aftermarket filtration for North American heavy-duty trucks. Here's what sets us apart:
IATF 16949 Certified Manufacturing: Our filters are produced in ISO/TS-certified facilities — the same quality standard used by OEM suppliers. Every batch undergoes multi-point QC inspection before shipping.
American Warehouse Stock: This product ships from our US warehouse within 1 business day. No 3-week wait from overseas dropshippers. Real inventory, real fast delivery.
Diesel Experts, Not Generalists: We focus exclusively on diesel filtration — fuel filters, oil filters, air filters, and CV filters for Class 6-8 trucks. When you call or email us, you're talking to people who know the difference between an ISX 11.9L and an ISX 15L.
Price Confidence: Save 40-60% vs. Cummins dealer pricing without sacrificing quality. Your truck earns money on the road — not in the shop waiting for overpriced parts.
Frequently Asked Questions
Q: What does the crankcase ventilation filter actually do?A: The CV filter (also called the engine breather filter) separates oil mist from the blow-by gases that escape past the piston rings during combustion. Clean gases are routed back to the intake; oil droplets are captured and returned to the crankcase. Without a functioning CV filter, oil vapor coats the turbocharger compressor, intercooler, and intake manifold — reducing efficiency and eventually causing component failure.
Q: How often should I replace the CV filter on my Cummins ISX?A: Cummins recommends replacement every 150,000 miles under normal highway operation. For trucks that idle extensively, run in dusty environments, or operate in severe-duty cycles (logging, mining, construction), replace at 100,000 miles. Many fleet maintenance programs bundle CV filter replacement with the 100K service interval as preventive insurance.
Q: What are the symptoms of a clogged CV filter?A: Watch for these warning signs: (1) Oil weeping from front/rear crank seals and oil pan gasket — the #1 telltale, (2) Increased oil consumption with no visible leaks on the ground, (3) Oil residue in the turbocharger inlet or charge air cooler boots, (4) Blue-white smoke from the exhaust under acceleration. Any of these symptoms warrant immediate CV filter inspection.
Q: Does this fit ISX 15L or X15 engines?A: No. This 904-7904 filter is specifically for the Cummins ISX 11.9L engine. The ISX 15L and X15 engines use different CV filter part numbers (typically 3685845 or equivalent). Always verify your engine displacement — the 11.9L ISX was offered alongside the 15L in many Kenworth and Peterbilt models.
Q: Is this an OEM Cummins filter?A: This is a high-quality aftermarket replacement manufactured to IATF 16949 standards — equivalent to OEM specifications. It replaces Cummins OE part numbers 904-7904, 3685528 and crosses to Fleetguard CV50617 and Baldwin CV50634. If you prefer genuine Cummins-branded packaging, we also carry that — contact us for availability.
📦 Ready to Ship: In-stock at our US warehouse. Orders placed before 2 PM ET ship same business day. Questions about fitment? Our diesel specialists respond within 2 hours.
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