Water Coolant Hose BMW E87 E90 Return Pipe Line 118d 120d 318d 320d 7789590

The BMW E87 E90 M47N2 Coolant Hose Pipe 7789590 is an original cooling system component from the Cooling System Hoses and Pipes group, designed for use in BMW cars with the M47N2 engine. This used OEM coolant hose ensures proper coolant flow, stabilizing the engine's operating temperature and supporting safe vehicle operation.

Specifications and technical data

• SKU: 7789590
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7789590
• Substitutable numbers: 17127789590, 7789590, BG
• Category: Hoses, Lines & Pipes

Purpose and Function in the Cooling System

The coolant hose in this BMW model is responsible for the controlled flow of coolant between system components, which directly impacts the maintenance of a stable M47N2 engine temperature. The appropriately selected geometry and inner diameter of the hose limit pressure drops, and the fitted connection spigots minimize the risk of leaks at the joints.

Using an original hose from this series allows for the preservation of the cooling system's factory operating characteristics, which is particularly important for diesel engines, sensitive to overheating and localized temperature differences in the engine block and cylinder head.

Benefits of Using an Original BMW Hose

Using a coolant hose dedicated to the BMW E87 and E90 with the M47N2 engine offers a range of practical operational benefits:

• factory fit to spigots and mounts in the engine bay,
• appropriately selected flexibility, facilitating installation and engine vibration compensation,
• maintenance of the correct coolant flow direction,
• reduced risk of micro-cracks and leaks typical of non-original replacements.

Thanks to this, the coolant hose operates stably under typical thermal load conditions, and the cooling system maintains parameters close to factory settings. This translates to more predictable engine behavior and a lower risk of overheating-related failures.

Component Condition and Installation Aspects

The offered coolant hose is a used component, which in practice means it comes from a dismantled vehicle and has been verified for its suitability for further use. This type of part is particularly attractive to users who want to maintain their car in OEM specification while optimizing service costs.

During installation, it is recommended to:

• check the condition of the sealing surfaces on the mating spigots,
• replace the hose clamps with new ones, matched to the hose diameter,
• bleed the cooling system after filling with fresh coolant,
• verify for leaks after the engine reaches operating temperature.

This approach allows for the full utilization of the used component's potential and reduces the risk of subsequent leaks.

Cooling System Optimization

A correctly selected coolant hose significantly impacts the even distribution of heat within the engine and the stability of the operating temperature. In conjunction with a functional coolant pump, thermostat, and radiator, the hose from this reference helps maintain the correct thermal balance of the engine, which translates to:

• more stable engine operation across the full range of loads,
• reduced risk of localized overheating,
• better operating conditions for engine oil,
• extended lifespan of components operating at high temperatures.

If you want to understand more broadly the impact of individual components on engine temperature, it is worth reading the article Engine Cooling System – Overheating, Repair, and Used Radiators, which discusses practical aspects of diagnostics and service.

Related BMW Cooling System Components

When planning maintenance work, it is worth considering a comprehensive inspection of the entire coolant circuit, including other hoses, connectors, and mating components. If you need additional components of this type for your car, check the available parts in the BMW Cooling System Hoses and Pipes category.