Original BMW F25 X3 and F26 X4 Engine Heat Exchanger Coolant Return Hose (2011–2018)

This Original BMW coolant return hose carries engine coolant through the heater circuit on the F25 BMW X3 and F26 BMW X4, covering 2011–2017 X3 sDrive28i, xDrive28i, and xDrive35i models and the 2015–2018 X4. BMW names the part Coolant hose, return, and places it in the engine heat exchanger group. Heater hoses move hot coolant from the engine through the heater core inside the dashboard, and the blower motor pushes air across that core to warm the cabin. The same coolant belongs to the engine cooling system, so a leaking heater hose lowers coolant level and can lead to overheating. This hose is made in Mexico and weighs 366 g (0.8 lb).

Original BMW Parts carry a 24-month parts warranty.

BMW has produced this return hose since September 2010, and the same part number serves both the F25 X3 and the F26 X4. BMW's parts data applies it across the N20 four-cylinder, the N52N six-cylinder, and the N55 turbocharged six, so one hose covers every engine in the store fitment. Coolant hoses for the heater core can deform with age and constant heating and cooling cycles. Warning signs include cracks in the hose surface, leakage at the connections near the firewall, rubber that has gone soft, a coolant smell under the hood or in the cabin after the heat has run, a dropping coolant level, and little or no heat from the vents.

Technical Details

• Manufacturer: BMW, Original BMW Parts
• Part number: 64-21-9-193-255
• BMW part name: Coolant hose, return
• Diagram group: Heat exchanger, engine
• Weight: 366 g (0.8 lb)
• Production start: September 2010
• Made in Mexico
• Sold as one hose
• Warranty: 24 months on Original BMW Parts

Common Questions

Is this the supply or the return heater hose?
BMW identifies this part as the coolant return hose in the engine heat exchanger group.

Does it fit both four-cylinder and six-cylinder X3 models?
Yes. BMW applies it to F25 X3 models with the N20 four-cylinder as well as the N52N and N55 six-cylinder engines.

Can a leaking heater hose hurt the engine?
It can. The heater hose shares coolant with the engine cooling system, so a leak lowers the coolant level and can cause overheating.

Fitment & Compatibility

Use the fitment table below to confirm the exact year, make, model, submodel, and any application notes before ordering. PMB Performance has spent over 20 years matching parts to vehicles and can verify this against your VIN.