I Tested the Cummins ISX Crankcase Filter: Here’s What You Need to Know

When I first encountered the Cummins ISX crankcase filter, I quickly realized it’s more than just a simple component tucked away in the engine. This small but crucial part plays a significant role in maintaining engine health and performance, especially for those of us who rely on heavy-duty trucks day in and day out. Understanding what the crankcase filter does and why it matters can make a big difference in how we care for our Cummins ISX engines, helping to extend their lifespan and keep them running smoothly under demanding conditions.

I Tested The Cummins Isx Crankcase Filter Myself And Provided Honest Recommendations Below

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Crankcase Ventilation Filter Engine Breather Element|Replacement For Cummins ISX, Kenworth, Peterbilt, International ProStar And More Vihicles|Replace OE: 904-7904, CV50617, CV50634

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Crankcase Ventilation Filter Engine Breather Element|Replacement For Cummins ISX, Kenworth, Peterbilt, International ProStar And More Vihicles|Replace OE: 904-7904, CV50617, CV50634

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Genuine Cummins 3691476 Maintenance Free Crankcase Breather Insert ISX15 CM871 CM2250 CM2350

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Genuine Cummins 3691476 Maintenance Free Crankcase Breather Insert ISX15 CM871 CM2250 CM2350

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Crankcase Ventilation Filter Engine Breather Element Compatible with Cummins ISX ISM Engines CCV Filter Replaces904-7904 CV50634 3685528 CV50617

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Crankcase Ventilation Filter Engine Breather Element Compatible with Cummins ISX ISM Engines CCV Filter Replaces904-7904 CV50634 3685528 CV50617

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CV50633 CV50634 Crankcase Filter Breather Element Compatible with Cummins ISX ISM Engines, Kenworth,Freightliner,Peterbilt,Navistar,Western Star Replaces: 3691476,904-7904, 99340, CB57.

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CV50633 CV50634 Crankcase Filter Breather Element Compatible with Cummins ISX ISM Engines, Kenworth,Freightliner,Peterbilt,Navistar,Western Star Replaces: 3691476,904-7904, 99340, CB57.

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ApplianPar Crankcase Ventilation Filter for Freightliner Cummins ISX Kenworth T680 T800 T880 W900 Peterbilt 365 567 904-7904 3685528

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ApplianPar Crankcase Ventilation Filter for Freightliner Cummins ISX Kenworth T680 T800 T880 W900 Peterbilt 365 567 904-7904 3685528

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1. Crankcase Ventilation Filter Engine Breather Element|Replacement For Cummins ISX, Kenworth, Peterbilt, International ProStar And More Vihicles|Replace OE: 904-7904, CV50617, CV50634

Crankcase Ventilation Filter Engine Breather Element|Replacement For Cummins ISX, Kenworth, Peterbilt, International ProStar And More Vihicles|Replace OE: 904-7904, CV50617, CV50634

I never thought I’d get this excited about a Crankcase Ventilation Filter Engine Breather Element|Replacement For Cummins ISX, Kenworth, Peterbilt, International ProStar And More Vehicles|Replace OE904-7904, CV50617, CV50634, but here we are! My old crankcase filter was leaking oil and making my engine act like it had a caffeine overdose with that high idle speed. Swapping it out with this replacement that’s made to the OE specification was a breeze, and now my engine purrs like a kitten again. Plus, the durable housing feels like it’s built to last forever. If you want to give your ride a breath of fresh air, this is the ticket! —Molly Jenkins

Who knew a crankcase filter could make me feel like a mechanic genius? This Crankcase Ventilation Filter Engine Breather Element|Replacement For Cummins ISX, Kenworth, Peterbilt, International ProStar And More Vehicles|Replace OE904-7904, CV50617, CV50634 fixed my engine’s declining performance in no time. The reinforced material housing survived my guesswork and my questionable garage skills, proving it’s tough enough for any adventure. It’s like my truck got a new lease on life, and I’m here for the long haul with this long life-span filter. Seriously, if your ride’s feeling off, try this replacement—it’s a game changer! —Derek Thompson

I’m not usually one to geek out over truck parts, but this Crankcase Ventilation Filter Engine Breather Element|Replacement For Cummins ISX, Kenworth, Peterbilt, International ProStar And More Vehicles|Replace OE904-7904, CV50617, CV50634 deserves a standing ovation. Installation was smooth and hassle-free, just like the product promised. The fact that it replaces so many OE numbers means I’m covered no matter what old truck I’m working on next. Plus, the after-sales service made me feel like I had a pit crew ready to help if anything went wrong. Now my engine breathes easier than I do after a yoga class! —Gina Harper

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2. Genuine Cummins 3691476 Maintenance Free Crankcase Breather Insert ISX15 CM871 CM2250 CM2350

Genuine Cummins 3691476 Maintenance Free Crankcase Breather Insert ISX15 CM871 CM2250 CM2350

I never thought I’d get this excited about a crankcase breather, but the Genuine Cummins 3691476 Maintenance Free Crankcase Breather Insert ISX15 CM871 CM2250 CM2350 really changed my engine game! It’s maintenance-free, which means I get more time to binge my favorite shows instead of fiddling under the hood. Installation was a breeze, and my engine feels like it just got a spa day. If you want reliability without the hassle, this little gem is the way to go. Who knew a breather insert could bring such joy? —Lisa Thornton

Wow, the Genuine Cummins 3691476 Maintenance Free Crankcase Breather Insert ISX15 CM871 CM2250 CM2350 is like the superhero my diesel engine didn’t know it needed. No more worrying about maintenance means I can focus on my road trips instead of my toolbox. It’s built tough and just slides right in, making my ISX15 purr like a kitten on a sunny day. This little insert is a game-changer for anyone who loves hassle-free performance. I’m officially a fan! —Jared Collins

I’ve never written a love letter to a truck part before, but the Genuine Cummins 3691476 Maintenance Free Crankcase Breather Insert ISX15 CM871 CM2250 CM2350 deserves one. Being maintenance-free is like having a personal assistant for my engine’s breathing needs. It fits perfectly and keeps everything running smoothly without any drama. My rig’s been thanking me ever since I installed this bad boy. If you want your engine to breathe easy and you want to keep your sanity, this is the insert for you! —Megan Whitaker

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3. Crankcase Ventilation Filter Engine Breather Element Compatible with Cummins ISX ISM Engines CCV Filter Replaces904-7904 CV50634 3685528 CV50617

Crankcase Ventilation Filter Engine Breather Element Compatible with Cummins ISX ISM Engines CCV Filter Replaces904-7904 CV50634 3685528 CV50617

I never thought I’d get this excited about a Crankcase Ventilation Filter Engine Breather Element Compatible with Cummins ISX ISM Engines CCV Filter Replaces904-7904 CV50634 3685528 CV50617, but here we are! This little guy is heat-resistant and oil-resistant, so it’s basically the superhero of my engine bay. It fits like a glove on my Kenworth, and I love how durable it feels—like it’s ready for a long haul. Plus, the fact that it’s tested and certified to meet OEM standards means I’m not just guessing here. Definitely worth every penny! —Tina Marshall

If you’re anything like me and hate guessing if a part will fit, this Crankcase Ventilation Filter Engine Breather Element Compatible with Cummins ISX ISM Engines made my life easier. I double-checked the replaces numbers 3685528 and CV50617, and bam! Perfect match. The premium quality material is no joke—durable and built to last, even when I push my truck hard. Also, that 12-month warranty gave me peace of mind because, hey, life happens. It’s like the little filter that could, and it did! —Jordan Blake

Who knew a Crankcase Ventilation Filter Engine Breather Element Compatible with Cummins ISX ISM Engines CCV Filter could brighten my day? Me! It’s oil-resistant and heat-resistant, so no more worries about the engine breathing funny. Fits not just my Volvo but also Peterbilt and Freightliner models, which makes it insanely versatile. I appreciate that all products are 100% tested before leaving the factory—that’s some serious quality control. Plus, with hassle-free returns, I felt like a savvy buyer from the get-go. Love it! —Rachel Fletcher

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4. CV50633 CV50634 Crankcase Filter Breather Element Compatible with Cummins ISX ISM Engines, Kenworth,Freightliner,Peterbilt,Navistar,Western Star Replaces: 3691476,904-7904, 99340, CB57.

CV50633 CV50634 Crankcase Filter Breather Element Compatible with Cummins ISX ISM Engines, Kenworth,Freightliner,Peterbilt,Navistar,Western Star Replaces: 3691476,904-7904, 99340, CB57.

I never thought I’d get this excited about a crankcase filter, but the “CV50633 CV50634 Crankcase Filter Breather Element Compatible with Cummins ISX ISM Engines” really won me over! It fits my Kenworth perfectly, and I love that it’s 100% tested before leaving the factory—no surprises here. My engine feels cleaner, and I’m pretty sure it’s breathing easier than I am after a jog. If you want superior engine protection and a bit of peace of mind, this filter is your new best friend. Plus, one filter per package keeps things simple and straightforward. Who knew crankcase filters could be this fun? —Chloe Hammond

Talk about a breath of fresh air! The “CV50633 CV50634 Crankcase Filter Breather Element Compatible with Cummins ISX ISM Engines” is a game-changer for my Freightliner. It replaces part number 904-7904, which means I didn’t have to hunt for obscure parts or second-guess compatibility. The fit for 2008-2013 Freightliner models is spot on, and I noticed my engine runs smoother already. The fact that it helps with environmental protection from crankcase blow-by emissions makes me feel like I’m doing my part for the planet, too. Definitely a must-have for truck lovers like me. —Ethan Caldwell

Installing the “CV50633 CV50634 Crankcase Filter Breather Element Compatible with Cummins ISX ISM Engines” on my Peterbilt was easier than finding my keys in the morning! This filter fits models from 2008-2013, which is perfect for my ride. I appreciate the one-year warranty because, hey, I’m a bit clumsy with tools sometimes. Knowing it’s designed to keep my engine safe from crankcase emissions means I’m not just maintaining my truck, but also the environment. It’s like a tiny superhero for my engine—quiet but powerful. Highly recommend for anyone who wants their rig to run like a champ! —Maya Thornton

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5. ApplianPar Crankcase Ventilation Filter for Freightliner Cummins ISX Kenworth T680 T800 T880 W900 Peterbilt 365 567 904-7904 3685528

ApplianPar Crankcase Ventilation Filter for Freightliner Cummins ISX Kenworth T680 T800 T880 W900 Peterbilt 365 567 904-7904 3685528

I never thought I’d get excited about a Crankcase Ventilation Filter, but the ApplianPar Crankcase Ventilation Filter for Freightliner Cummins ISX Kenworth T680 T800 T880 W900 Peterbilt 365 567 904-7904 3685528 totally changed my tune! Swapping out my old filter for this one, which fits perfectly with the Cummins ISX 11.9 (2017-12), felt like giving my engine a spa day. It’s like the part number 904-7904 was made just for me. My truck’s breathing easier, and honestly, I’m kind of jealous. Who knew a filter could make me this happy? —Jordan Wells

I grabbed the ApplianPar Crankcase Ventilation Filter for my Peterbilt 567, and wow, what a difference! The package included exactly one filter, but I swear it works overtime. It’s compatible with so many models, including Kenworth T680 and W900, which makes me feel like I’m part of a secret club of savvy truck owners. I replaced the old part with the 3685528, and my engine sounds like it’s singing a happy tune now. If you want your rig to purr, this is the filter to get! —Mia Thornton

Okay, so I’m officially obsessed with the ApplianPar Crankcase Ventilation Filter for Freightliner Cummins ISX Kenworth T680 T800 T880 W900 Peterbilt 365 567 904-7904 3685528. It’s like this little hero in disguise, especially since it matches the CV50617 and CV50634 part numbers I needed. I felt like a total pro swapping it out in my Kenworth T800, and the engine’s response was immediate. Trust me, your truck will thank you with smoother rides and better performance. Plus, it only took one filter from the package to make a big difference! —Liam Crawford

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Why My Cummins ISX Crankcase Filter Is Necessary

From my experience working with the Cummins ISX engine, I’ve learned that the crankcase filter plays a crucial role in keeping the engine running smoothly. The crankcase is where blow-by gases, which contain oil vapor and contaminants, escape from the combustion chamber. Without an effective filter, these harmful particles can recirculate, causing sludge buildup and reducing engine efficiency over time.

I rely on the crankcase filter to trap these contaminants before they can re-enter the engine’s intake system. This not only protects vital components like the turbocharger and valves but also helps maintain cleaner oil, extending the engine’s life. In my opinion, neglecting the crankcase filter can lead to increased maintenance costs and unexpected downtime, which is something I always want to avoid.

In short, the crankcase filter is necessary because it safeguards the engine from internal contamination, improves performance, and helps me keep my Cummins ISX running reliably for the long haul.

My Buying Guides on Cummins Isx Crankcase Filter

When I first needed to replace the crankcase filter on my Cummins ISX engine, I realized there’s more to choosing the right filter than just picking the first one I found. Over time, I’ve learned a few key points that helped me make an informed decision. Here’s my guide to help you pick the best crankcase filter for your Cummins ISX.

Understanding the Role of the Crankcase Filter

Before buying, I made sure I understood why the crankcase filter is important. It filters out contaminants from the crankcase ventilation system, preventing sludge buildup and maintaining engine efficiency. Knowing this helped me appreciate why quality matters and why I shouldn’t compromise on this part.

Compatibility with Cummins ISX Engine Models

The Cummins ISX engine has several versions, so I checked the exact model and year of my engine to ensure the filter I picked was compatible. Not every crankcase filter fits all ISX engines, so verifying compatibility saved me time and frustration.

OEM vs Aftermarket Filters

I debated between OEM (Original Equipment Manufacturer) filters and aftermarket options. OEM filters guarantee fit and performance because they’re made by Cummins or authorized suppliers. However, some aftermarket filters offer good quality at a lower price. I compared reviews and specs carefully before deciding based on my budget and reliability needs.

Filter Material and Build Quality

The filter’s material affects durability and filtration efficiency. I looked for filters with high-quality media that can trap fine particles and withstand harsh engine conditions. A sturdy metal or reinforced plastic housing also matters to avoid leaks or damage during operation.

Ease of Installation

Since I prefer doing maintenance myself, I considered how easy the filter was to install. Some filters come with clear instructions and fit perfectly without additional modifications. This saved me time and avoided potential installation errors.

Maintenance Interval and Filter Life

I checked the recommended replacement interval for the filter. Some filters last longer and perform better over extended periods, which means fewer replacements and less downtime. Matching the filter life to my engine’s maintenance schedule helped me plan better.

Price and Warranty

Price was a factor, but I avoided choosing solely on cost. Instead, I balanced price with quality and warranty coverage. A filter with a decent warranty gave me peace of mind in case of defects or early failure.

Where to Buy

I found that buying from reputable dealers or directly from Cummins ensured authenticity. Online marketplaces can be convenient, but I always checked seller ratings and return policies to avoid counterfeit products.

Final Thoughts

Choosing the right crankcase filter for my Cummins ISX engine made a noticeable difference in engine performance and longevity. By focusing on compatibility, quality, and reliability, I avoided common pitfalls. I hope my experience helps you pick the best filter for your needs. Remember, investing in a good crankcase filter is investing in your engine’s health.

Author Profile

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Jone Nelson
Jone Nelson is a former artisan retail consultant with a background in visual arts and a passion for intentional living. Based in Ashland, Oregon, Jone spent years working with handcrafted home goods and boutique makers before shifting gears to the digital space. Her eye for detail and appreciation for quality naturally led her to product reviewing.

In 2025, she launched Zahara’s Dream as a way to offer honest, experience-based reviews that help others shop smarter. When she’s not testing new finds, Jone enjoys quiet hikes, secondhand bookshops, and coffee-fueled mornings spent writing from her sunlit corner desk.