--- title: "Not All Diesel Exhaust Fluid Is the Same: Compare Options" description: Learn why all DEF aren’t the same, and which one reigns supreme as the best diesel exhaust fluid on the market. Place an order & get free shipping. image: https://info.kellerheartt.com/hubfs/shutterstock_1474664123.jpg --- [![keller-heartt-oil](https://info.kellerheartt.com/hubfs/branding/keller-heartt-logo.200.png)](https://www.kellerheartt.com/) - Shop By Industry - [Trucking & Automotive](https://www.kellerheartt.com/collections/commercial-truck-supplies) - [Diesel Exhaust Fluid](https://www.kellerheartt.com/collections/diesel-exhaust-fluid) - [Motor Oil](https://www.kellerheartt.com/collections/motor-oil) - [Brake Cleaner](https://www.kellerheartt.com/collections/brake-cleaner) - [Antifreeze](https://www.kellerheartt.com/collections/antifreeze-coolants) - [Transmission Fluid](https://www.kellerheartt.com/collections/transmission-fluid) - [Machine Shops & Metalworking](https://www.kellerheartt.com/collections/metalworking-fluids) - [Cutting Oil](https://www.kellerheartt.com/collections/cutting-oil) - [Coolant](https://www.kellerheartt.com/collections/tool-die-coolants) - [Hydraulic Oil](https://www.kellerheartt.com/collections/hydraulic-oil) - [Soluble Oil](https://www.kellerheartt.com/collections/soluble-oil) - [Rust Preventative](https://www.kellerheartt.com/collections/tool-die-rust-veto) - [Industrial](https://www.kellerheartt.com/collections/industrial-products) - [Hydraulic Oil](https://www.kellerheartt.com/collections/hydraulic-oil) - [Industrial Gear Oil](https://www.kellerheartt.com/collections/industrial-gear-oil-all-sizes-brands) - [Multi-Purpose Grease](https://www.kellerheartt.com/collections/multi-purpose-grease) - [Cleaner & Degreaser](https://www.kellerheartt.com/collections/industrial-cleaners-descalers-degreasers) - [Ethylene Glycol](https://www.kellerheartt.com/collections/ethylene-glycol) - [Food & Beverage](https://www.kellerheartt.com/collections/food-grade-oils-lubricants) - [Propylene Glycol](https://www.kellerheartt.com/collections/propylene-glycol-drums) - [Cassida Fluid & Grease](https://www.kellerheartt.com/collections/cassida-lubricants-greases) - [Fuchs Gear Oil & Grease](https://www.kellerheartt.com/collections/fuchs-lubricants) - Shop By Brand - [Shell Products](https://www.kellerheartt.com/collections/shell-oil-lubricants) - [TRUEGARD Products](https://www.kellerheartt.com/collections/truegard-oil-lubricants) - [Blue DEF Products](https://www.kellerheartt.com/collections/bluedef) - [Oil Eater Products](https://www.kellerheartt.com/collections/oil-eater) - [Blog](https://info.kellerheartt.com/blogs) - [Request a Quote](https://www.kellerheartt.com/pages/request-a-quote) [Contact Us](https://www.kellerheartt.com/pages/contact-us) Diesel Exhaust Fluid # Is All Diesel Exhaust Fluid the Same? How to Compare Your Options [Brian McGrath](https://info.kellerheartt.com/blogs/author/brian-mcgrath) Mar 26, 2025 --- Diesel exhaust fluid (DEF) has become an essential component in modern diesel engines, particularly those equipped with selective catalytic reduction (SCR) systems. While all DEF products are designed to meet certain standards, discerning users understand that [not all DEFs are created equal](https://info.kellerheartt.com/blogs/faqs-about-diesel-exhaust-fluid-storage). Subtle differences in quality can significantly impact engine performance and longevity.  This selection guide was created to help you understand nuances of DEF, the importance of adhering to standards like ISO 22241, and how to select the best DEF for your needs. ## Understanding Diesel Exhaust Fluid (DEF) DEF is a non-toxic, colorless, and non-flammable solution composed of 32.5% high-purity urea and 67.5% deionized water. Its primary function is to reduce harmful nitrogen oxide (NOx) emissions from diesel engines. When injected into the exhaust stream of an SCR-equipped engine, DEF undergoes a chemical reaction that transforms NOx into harmless nitrogen and water vapor, thereby mitigating environmental pollution. ## ISO 22241: What Does It Mean & Why Does It Matter for DEF? To ensure DEF's efficacy and compatibility with SCR systems, it must conform to the [ISO 22241 standard](https://cdn.standards.iteh.ai/samples/66408/174c8dca13bd4712953507c3d1e1f6d1/ISO-22241-1-2019.pdf). This international standard specifies the quality characteristics of DEF, ensuring that it meets the necessary purity and composition requirements.  Adherence to ISO 22241 is crucial, as using substandard DEF can lead to SCR system malfunctions, increased emissions, and potential engine damage. [![Download Now ►](https://no-cache.hubspot.com/cta/default/23289434/interactive-175215758477.png)](https://info.kellerheartt.com/hs/cta/wi/redirect?encryptedPayload=AVxigLL8WMqGOyqaFsyqQ%2Bnu8iWkWPhtSjS3JgaiRwqzApE859oKAC%2BcHueMrSGINtCGez6V1pJyh7gM1VGWIvoiqAGWSYC8bk9Nun4MzAFQUEqyCogFxdyqcd5zb5bxXWqIM5WqPcrt%2BIhQdXH2u9CBlgpnmsduaFHbz7Q4pNNKq8wISx4nVj8nshfHJZGpdJD1EdbYfllCHOJ%2FI6WSH34lZvEOeW2PNJiwRr3C%2Fw%3D%3D&webInteractiveContentId=175215758477&portalId=23289434) ## Comparing DEF Options? Keep These Things In Mind Before you choose the first DEF product that you see in a store or that shows up on your Google search, take a second to really get to know your options. There are some DEF products that are better at protecting your engine and ensuring optimal performance than others.  Here are a few things you’ll want to look for when exploring your options. ### High Purity Standards Impurities in DEF can clog the SCR catalyst, leading to system inefficiencies or failures. Ensure the DEF you choose is free from contaminants and meets the stringent purity requirements outlined in ISO 22241. ### Manufacturer Reputation Established manufacturers with a history of producing high-quality DEF are more likely to provide reliable products. Researching customer reviews and industry feedback can offer insights into a manufacturer's credibility. ### Availability and Distribution Network Consistent access to DEF is vital, especially for businesses operating fleets. Opt for brands that have a robust and reliable distribution network, ensuring product availability when you need it. ### Packaging and Sizes DEF is available in various packaging options, from small containers for personal vehicles to bulk deliveries for large fleets. Choose a supplier that offers packaging sizes aligning with your consumption needs. ### API Registration and OEM Specifications The [American Petroleum Institute (API) provides a certification program for DEF products](https://www.api.org/products-and-services/diesel-exhaust-fluid), ensuring they meet specific quality standards. Additionally, verify that the DEF aligns with or exceeds Original Equipment Manufacturer (OEM) specifications for your vehicle or equipment. ## Our Top DEF Recommendation: BlueDEF Among the many DEF products available, [we recommend BlueDEF](https://info.kellerheartt.com/blogs/better-to-be-blue-improving-diesel-engines-bluedef) most often to our customers. It sets the industry standard as the best diesel exhaust fluid. Here’s why. - It’s ISO 22241 compliant. - It’s API certified. - It meets (and sometimes exceeds) all OEM specifications. - It’s formulated using the highest-purity synthetic urea and deionized water, reducing the risk of contaminants in your SCR system(s).  - It’s available in various quantities, ranging from 1-gallon containers to bulk deliveries. [Shop BlueDEF (and get free shipping!) here →](https://www.kellerheartt.com/collections/bluedef) ## Looking for a Reliable BlueDEF Supplier? Look No Further Selecting the right DEF is only part of the equation; partnering with a reputable supplier ensures consistent product quality and availability.  At Keller-Heartt, we’re dedicated to ensuring you get the high-quality DEF you need exactly when you need it. With a range of quantities, fast and free shipping, and an exceptional customer service team to back it all up, we can be the one-stop shop you need to keep your vehicle or fleet running. [Shop BlueDEF →](https://www.kellerheartt.com/collections/bluedef) [Shop all DEF products →](https://www.kellerheartt.com/collections/diesel-exhaust-fluid) [Diesel Exhaust Fluid](https://info.kellerheartt.com/blogs/tag/diesel-exhaust-fluid) #### FOLLOW AND SHARE: [![share on facebook](https://info.kellerheartt.com/hs-fs/hubfs/images/social/icons/facebook-color.png?width=45&height=45&name=facebook-color.png)](https://www.facebook.com/pages/Keller-Heartt-Company/170082969671892?ref=hl) [![follow us on youtube](https://info.kellerheartt.com/hs-fs/hubfs/images/social/icons/youtube-color.png?width=45&height=45&name=youtube-color.png)](https://www.youtube.com/channel/UCA9e_Yo_qd4PqpK2dDdgxaw) [![follow us on instagram](https://info.kellerheartt.com/hs-fs/hubfs/images/social/icons/instagram-color.png?width=45&height=45&name=instagram-color.png)](https://www.instagram.com/keller.heartt/?hl=en) [![follow us on twitter](https://info.kellerheartt.com/hs-fs/hubfs/images/social/icons/twitter-color.png?width=45&height=45&name=twitter-color.png)](https://twitter.com/KellerHeartt) [![follow us on linkedin](https://info.kellerheartt.com/hs-fs/hubfs/images/social/icons/linkedin-color.png?width=45&height=45&name=linkedin-color.png)](https://www.linkedin.com/company/keller-heartt-oil/) [Shop by Brand ►](https://www.kellerheartt.com/collections/shop-by-brand) ## Similar posts Diesel Exhaust Fluid ### [Troubleshooting Common DEF Issues in Trucks](https://info.kellerheartt.com/blogs/troubleshooting-common-def-issues-in-trucks) Troubleshoot common Diesel Exhaust Fluid (DEF) issues in trucks, learn best practices for maintenance, and ensure your fleet runs smoothly and... Brian McGrath Aug 9, 2024 DEF Shortages ### [Stay Ahead of the DEF Shortages in 2025: What Fleet Managers & Diesel Mechanics Need to Know](https://info.kellerheartt.com/blogs/def-shortages-2025) Don’t get caught off guard—DEF shortages are coming. Discover what's driving them, the market outlook, and how to keep your fleet moving in 2025 &... Brian McGrath May 16, 2025 BlueDEF ### [FAQs About Diesel Exhaust Fluid Storage](https://info.kellerheartt.com/blogs/faqs-about-diesel-exhaust-fluid-storage) With the rising popularity of diesel exhaust fluid (DEF) comes ample questions about this vital automotive fluid. Read on for answers to our FAQs. Brian McGrath Mar 1, 2024 ## **Get the latest oil & lubricant industry insights** Subscribe to the Keller-Heartt blog so you can sharpen your industry knowledge, gather helpful tips, and stay informed about changes or updates in the oil provider landscape. ### Subscribe to Our Blog! © 2025 Keller-Heart Oil All rights reserved ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Brian McGrath", "url" : "https://info.kellerheartt.com/blogs/author/brian-mcgrath" }, "dateModified" : "2025-03-26T13:13:31.374Z", "datePublished" : "2025-03-26T13:13:31.000Z", "headline" : "Not All Diesel Exhaust Fluid Is the Same: Compare Options", "image" : [ "https://info.kellerheartt.com/hubfs/shutterstock_1474664123.jpg" ], "mainEntityOfPage" : { "@id" : "https://info.kellerheartt.com/blogs/best-diesel-exhaust-fluid-options", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://info.kellerheartt.com/hubfs/branding/keller-heartt-logo.350.png" }, "name" : "Keller-Heartt Co" } } ```