Dayco 71578 Radiator Coolant Hose - Lower or Lower - Pipe To Radiator

Product Overview

Dayco 71578 is a curved radiator coolant hose built for cooling-system service on select applications. It uses EPDM construction and a single I.D. hose design to match the required coolant path and connection size.

Compatible with Toyota Sienna cooling-system applications and Pontiac Sunbird lower hose routing, this hose is specified for fitment-based replacement work where the original hose shape and diameter matter. Part number 71578 is also referenced by several aftermarket and OE cross numbers for the same application.

Key Features

• EPDM rubber construction for coolant-system use
• Curved hose profile for application-specific routing
• Single I.D. hose design
• 1 5/16 in. inside diameter at both ends
• Built to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications

Detailed Description

Dayco 71578 is a radiator coolant hose designed around the original routing and connection requirements of the application. The EPDM material is commonly used in cooling systems for its resistance to heat and coolant exposure, while the curved shape helps follow the factory hose path without forcing the hose into an incorrect bend. This part number, 71578, fits 2011-2016 Toyota Sienna, lower, and 1992-1994 Pontiac Sunbird, lower - pipe to radiator.

The hose measures 1 5/16 inches inside diameter at each end and is identified as a single I.D. hose. It meets SAE J20R4 Class D-1 and SAE J1684 Type EC standards, giving buyers a clear specification reference when replacing a worn or damaged coolant hose on a Toyota Sienna or Pontiac Sunbird. This part cross-references Gates (e.g., 22403, 23804) for the same application.

What It Is Used For

• Replacing a cracked or softened radiator coolant hose
• Restoring proper coolant flow through the lower hose circuit
• Addressing leaks at hose ends caused by age or heat cycling
• Correcting fitment issues from an incorrect hose shape or diameter
• Servicing cooling-system repairs on select Toyota Sienna and Pontiac Sunbird applications

Installation Notes and Tips

Verify the hose routing, end diameter, and position before installation. Match the curved profile to the factory layout and inspect adjoining clamps, necks, and pipes for wear or corrosion before installing the new hose. Confirm fitment against the vehicle application data for the Toyota Sienna or Pontiac Sunbird listed above.

Quality Assurance

Dayco manufactures cooling-system hoses to published SAE specifications, including SAE J20R4 Class D-1 and SAE J1684 Type EC, to support consistent material and dimensional requirements.