Dayco 71791 Engine Coolant Bypass Hose

Dayco Curved Radiator Hose for Mercedes-Benz

Dayco Part Number 71791 is an engine coolant bypass hose built for select Mercedes-Benz applications that use a curved radiator hose layout. Made from EPDM rubber and finished in black, it is shaped for the specified coolant routing and sized with 1 13/32-inch inside diameters at both ends.

The Dayco Curved Radiator Hose line focuses on application-specific hose geometry for cooling system service. This hose follows the curved routing needed in the listed Mercedes-Benz E320, S320, C280, C36 AMG, SL320, 300CE, 300E, 300SE, and 300TE applications, helping maintain proper coolant flow path and fitment alignment.

• EPDM construction for cooling system use
• Black finish
• Single I.D. hose design
• 1 13/32-inch inside diameter at both ends
• Built to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications
• No heat shield and no protective sleeve

Detailed Product Overview

This Dayco 71791 hose is an engine coolant bypass hose designed for curved radiator hose applications on select Mercedes-Benz models. The EPDM material is commonly used in coolant service for its resistance to heat and fluid exposure, while the single I.D. hose construction supports a direct replacement style fit for the specified routing. Use Dayco 71791 when servicing cooling system hose wear on 1992-1998 Mercedes-Benz vehicles listed below.

Fits 1994-1998 Mercedes-Benz E320, N/A; Fits 1994-1998 Mercedes-Benz S320, N/A; Fits 1994-1997 Mercedes-Benz C280, N/A; Fits 1995-1997 Mercedes-Benz C36 AMG, N/A; Fits 1994-1997 Mercedes-Benz SL320, N/A; Fits 1993 Mercedes-Benz 300CE, N/A; Fits 1993 Mercedes-Benz 300E, N/A; Fits 1992-1993 Mercedes-Benz 300SE, N/A; Fits 1993 Mercedes-Benz 300TE, N/A.

This part cross-references Duralast B71791 for the same application.

Common Cooling System Issues

• Cracked or hardened radiator hose material
• Coolant seepage at the hose connection points
• Restricted coolant flow from a deteriorated bypass hose
• Incorrect hose routing on a curved Mercedes-Benz cooling path
• Service replacement for aging OEM-style coolant hoses

Installation Notes and Tips

Verify the hose routing, end diameters, and curved profile against the removed part before installation. Inspect adjoining clamps, necks, and coolant passages for wear or corrosion, and confirm the cooling system is properly filled and bled after service. Part Number 71791 should be matched to the exact Mercedes-Benz application listed above.

Quality Assurance

Dayco manufactures this hose to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications for cooling system service. The EPDM construction and application-specific shape support consistent replacement fitment for the listed Mercedes-Benz models.