Gates 51991 HVAC Heater Hose - Thermostat To Water Pump or Water Pump To Thermostat

Gates 51991 Molded Coolant Hose

Gates 51991 is a molded coolant hose built for heater and coolant routing where a formed EPDM hose is required. It is shaped for direct replacement use on Land Rover cooling system applications, including water pump to thermostat and thermostat to water pump routing.

The Gates Molded Coolant Hose line covers upper, lower, bypass, heater, and other coolant hose applications with OEM-quality specifications. For Land Rover Defender, Discovery, Range Rover, Range Rover Sport, and LR4 service work, this hose helps restore the original hose path without the need to source a dealer-only radiator hose replacement.

Key Features

• EPDM construction for coolant-system durability
• 1.5 in. / 38 mm inside diameter at both ends
• 7.75 in. centerline length for formed routing
• No spring included
• Single-branch design with zero branch quantity
• Direct replacement for molded heater and coolant hose applications

Detailed Description

Gates 51991 is a molded coolant hose engineered for precise routing between the water pump and thermostat on select Land Rover vehicles. The EPDM material is suited for hot coolant exposure and the molded shape supports proper hose alignment in tight engine compartments. This part number is used across multiple Land Rover cooling system applications, including Defender 110, Defender 130, Defender 90, Discovery, Range Rover Sport, Range Rover, and LR4 coverage.

This part cross-references URO LR033994 for the same application. If you are replacing a Land Rover heater hose or molded coolant hose, Gates 51991 provides the correct formed profile for service on 2010-2024 Land Rover cooling systems.

What It Helps Fix

• Coolant leaks from a cracked or aged molded hose
• Improper hose routing after cooling system service
• Softening, swelling, or deterioration of the original EPDM hose
• Restricted coolant flow caused by a damaged hose path
• Fitment issues when replacing a dealer-specific Land Rover hose

Installation Notes

Verify the hose routing and connection points before installation. This hose is listed for water pump to thermostat and thermostat to water pump positions, so confirm the vehicle-specific layout on the Land Rover Defender, Discovery, Range Rover, Range Rover Sport, or LR4 before removal. Inspect adjoining clamps, thermostat housing, and water pump outlets for wear or corrosion during service.

Quality Assurance

Gates manufactures this molded coolant hose to OEM-quality specifications for replacement use in Land Rover cooling systems. The Gates 51991 part number is supported by broad molded-hose coverage across upper, lower, bypass, and heater applications within the brand’s replacement line.