Gates 18204 HVAC Heater Hose

Gates Molded Heater Hose 18204 Overview

The Gates 18204 molded heater hose is an OEM-style coolant hose built for tight engine bays where a straight hose will not route correctly. Made from EPDM and factory-molded to its shape, it supports coolant, water, and air transfer in HVAC and engine cooling applications, and it is also approved for marine use.

This Gates Molded Heater Hose line is focused on small inside-diameter, formed hoses that match original routing more closely than universal hose stock. For vehicles such as the Nissan 240SX, Saturn L300, and Mitsubishi Mirage, the molded profile helps maintain proper hose path in compact engine compartments.

Key Features

• Brand: Gates Molded Heater Hose
• Part number: 18204
• EPDM construction for coolant and heater service
• Factory-molded shape for OEM-style routing
• End inside diameter: 0.31 in. (8 mm) at both ends
• Centerline length: 11.9 in. (302 mm)
• Use in coolant, water, and air applications
• Approved for marine applications

Detailed Description

Gates 18204 is a molded HVAC heater hose made for applications that require a formed hose with a small inside diameter and precise routing. Its EPDM material is suited for coolant transfer and related thermal management service, while the molded construction helps it follow the original hose path in crowded engine compartments. This part number is used across a wide range of import vehicles, including Nissan, Saturn, Mitsubishi, Toyota, Acura, Suzuki, and Volkswagen applications. If you are replacing a formed heater hose on a Nissan 240SX, Saturn L300, or Mitsubishi Mirage, the Gates 18204 provides an OE-style replacement profile for the listed positions.

This part cross-references Bosch 18204 for the same application.

Common Problems This Hose Can Address

• Cracked or hardened heater hose material
• Coolant leaks at a formed hose section
• Poor hose routing in tight engine compartments
• Incorrect fit from a universal straight hose
• Degraded hose performance in coolant, water, or air service

Installation Notes and Tips

• Verify the listed year, make, model, and position before ordering.
• Match the molded shape to the original hose routing for proper clearance.
• Inspect adjoining clamps, pipes, and fittings for wear before installation.
• Confirm both ends measure 8 mm (0.31 in.) inside diameter.
• Check for leaks after refilling the cooling system and bringing the engine to operating temperature.

Quality Assurance

Gates is known for OE-style hose construction and application-specific molded routing. Part number 18204 is built to meet the dimensional and material requirements called out for the listed HVAC heater hose applications.