1665003975 Coolant Hose for BMW Mercedes-Benz ML GLE W166 2012-2019 4.7L 5.5L

◆ This coolant hose is a direct replacement for the original Mercedes-Benz unit, designed to transport engine coolant between the radiator and the valve as part of the cooling system circuit.

◆ The OEM reference number is 1665003975 (also written as A1665003975 or 166-500-39-75). A related superseded reference is 166500397539.

◆ Mercedes-Benz catalog description specifies this as “hose to valve” for radiator-mounted applications on 4.6L and 4.7L biturbo engines .

◆ It is primarily designed for Mercedes-Benz GL-Class (X166) and GLS-Class (X166) models equipped with the M278 4.6L/4.7L V8 biturbo engine, covering model years from approximately 2013 through 2019 .

◆ This product is a coolant hose manufactured to meet original quality standards for fit, coolant flow, and durability.

◆ Part Number: 1665003975 / A1665003975

◆ Component Type: Coolant Hose / Coolant Line

◆ Vehicle Make: Mercedes-Benz

◆ Engine Compatibility: 4.6L V8 Biturbo, 4.7L V8 Biturbo (M278)

◆ Placement: Radiator-mounted, hose to valve

◆ Catalog Description: “4.6l biturbo, radiator mounted, hose to valve. 4.7l biturbo, radiator mounted, hose to valve.”

◆ Note: Clamps and mounting hardware are typically separate parts and are not included

◆ OEM Standard Fit: Manufactured to exact original specifications for a direct, hassle-free replacement.

◆ Cooling System Integrity: Maintains proper coolant circulation between radiator and engine components under high thermal load.

◆ Durable Construction: Built with materials resistant to heat, coolant exposure, and engine bay conditions.

◆ Cost-Effective Solution: An ideal alternative to costly dealership parts without compromising on fit or function.

◆ Mercedes-Benz GL450 (X166): 2013–2014 (4.6L/4.7L V8 Biturbo)

◆ Mercedes-Benz GL550 (X166): 2013–2016 (4.6L/4.7L V8 Biturbo)

◆ Mercedes-Benz GLS550 (X166): 2017–2019 (4.6L/4.7L V8 Biturbo)

◆ Additional fitments reported for GLE63 AMG and GLS63 AMG models; verify by part number before ordering .

◆ Note: Verify against your vehicle’s original part number and engine code before ordering, as fitment may vary by market and production period.

Q1: Is this a genuine Mercedes-Benz part?

A: The 1665003975 reference is the original equipment part number. Both genuine Mercedes-Benz and aftermarket equivalents are available that match the original fit and function .

Q2: How do I confirm if it fits my vehicle?

A: Check your vehicle’s existing part number. If your current coolant hose is stamped with 1665003975 or A1665003975, this replacement will fit. Also confirm your vehicle is a GL-Class or GLS-Class (X166) equipped with the 4.6L or 4.7L biturbo V8 engine, produced between 2013 and 2019 .

Q3: What are the symptoms of a failing coolant hose?

A: Common signs include coolant leaks under the vehicle, low coolant level warnings, engine overheating, and visible cracks or bulges on the hose. Inspect the hose regularly, especially at connection points, for signs of wear or degradation .