Gates 18121 HVAC Heater Hose

Gates 18121 Molded Heater Hose Overview

The Gates 18121 molded heater hose is an OEM-style coolant hose built for tight engine bays and small-diameter routing. With a 6 mm inside diameter at both ends and an 11-inch centerline length, it is shaped for direct routing in HVAC and cooling system applications on select Mazda, Acura, Suzuki, Oldsmobile, Ford, and Kia vehicles.

Gates Molded Heater Hose products are formed to follow factory-style bends, helping maintain proper hose routing where straight hose would not match the original path. This part number 18121 is made from EPDM and is approved for coolant, water, air, and marine applications.

Key Features

• EPDM construction for coolant and heater service
• Factory-molded shape for compact engine compartments
• 6 mm inside diameter at both ends
• 11-inch centerline length for OE-style routing
• Suitable for coolant, water, and air applications
• Approved for marine applications
• Gates molded heater hose part number 18121

Detailed Description

Gates 18121 is a molded HVAC heater hose designed to follow the original hose path in vehicles with tight packaging around the throttle body, EGR valve, reservoir, or pipe connections. It is a direct-fit style hose for applications such as 2004-2009 Mazda 3, 2003-2008 Mazda 6, 2006-2008 Suzuki Grand Vitara, 1996-2004 Acura RL, and 1993-1997 Ford Probe. The molded profile helps preserve routing clearance and connection alignment in systems that use a small I.D. hose.

This hose is also listed for 1999-2002 Oldsmobile Intrigue, 2001-2002 Oldsmobile Aurora, 1997 Kia Sephia, and 1993-1997 Mazda 626 and Mazda MX-6. If you are replacing a worn heater hose on a Mazda 3 throttle body heater circuit or a Mazda 6 EGR-to-throttle-body route, Gates 18121 provides the molded shape needed for the original layout. This part cross-references Bosch 18121 for the same application.

Common Repair Uses

• Replacing a cracked or softened heater hose
• Restoring coolant flow in a throttle body heater circuit
• Fixing leaks at molded hose bends and connection points
• Correcting hose routing in compact engine compartments
• Addressing hose deterioration from heat and age

Installation Notes and Tips

Verify the hose path, end diameters, and centerline length before installation. Match the vehicle position and notes exactly, especially on applications marked 2nd design or cut to fit. Inspect adjoining fittings, clamps, and pipe ends for corrosion or damage before installing the new hose. Confirm the hose is routed without twist or kinks so coolant flow and clearance remain consistent.

Quality Assurance

Gates manufactures this molded heater hose as an OE-style replacement with factory-shaped routing and EPDM material for HVAC and cooling system service. Part number 18121 is built to the dimensional and application requirements listed above for confirmed vehicle coverage.