Cummins | DEF Header | 5511561
Aftermarket DEF header replaces OEM 4378044 & more. No core required. Built to OEM specs for performance and durability. Backed by manufacturer warranty.
Cummins | DEF Header | 5511561
The DEF Header 5511561 is a premium aftermarket replacement for OEM Cummins part 4378044, engineered for heavy-duty performance and long-lasting reliability. Built to meet or exceed OEM standards, this Diesel Exhaust Fluid (DEF) header supports accurate fluid monitoring and delivery within SCR systems, helping maintain emissions compliance and engine efficiency. Manufactured using high-grade, corrosion-resistant materials, it offers excellent durability in high-temperature environments and resists DEF crystallization and failure common in lower-quality units.
This direct-fit DEF header requires no core return, simplifying installation and reducing downtime for fleet operators and service professionals. Ideal for trucks running Cummins diesel engines, it ensures seamless integration with existing DEF system components while providing consistent, accurate performance. Designed with OEM compatibility in mind, the 5511561 delivers the reliability needed to keep your vehicles road-ready and emissions compliant.
American Radiator offers this part with fast shipping and full manufacturer warranty support, ensuring peace of mind and dependable service. For customers seeking a high-quality DEF header that balances performance and cost, the 5511561 is the smart aftermarket solution. Enhance your SCR system’s performance with this trusted replacement, available now at American Radiator.
DEF Header Features:
Designed For:
Manufacturer Warranty
DuraWRX provides a manufacturer's warranty on its DEF-related products for up to 2 years/40,000 miles/1,200 hours (whichever occurs first). This warranty covers any defects in materials or workmanship. To be eligible for a claim, the end user must register their product purchase on the DuraWRX site. To file a claim, customers must contact DuraWRX to receive a return shipping label. Once the product is returned and the claim is approved, DuraWRX will issue either a refund or a credit.
DEF Header Specs:
Please confirm your OEM or Aftermarket number matches before ordering.
4378044
4378046
5511559
5511561
ASP-908-2317-564
ASP9082317564
Shipping & Returns
Why Buy From American Radiator?
Trust American Radiator, your reliable source for quality cooling solutions since 2001. With roots in the industry dating back to the 1970s, our team brings decades of experience delivering high-performance radiators, charge air coolers, and DPF systems at competitive prices.
We work directly with trusted domestic and international manufacturers that supply OEM-grade components, ensuring every product meets or exceeds original equipment standards. Whether you need a heavy-duty truck radiator or a replacement for your DEF Header, we’re committed to providing durable, cost-effective solutions that perform.
Have questions? Contact our experienced inside sales team at 888-483-5763 for expert guidance and fast, friendly support.
| Part Number | SKU | 251561 |
|---|---|
| OEM | Aftermarket Numbers | 4378044 4378046 5511559 5511561 ASP-908-2317-564 ASP9082317564 |