Original BMW Coolant Pipe, Expansion Tank to Cylinder Head, for BMW 5 Series, 6 Series Gran Turismo, and 7 Series (2016–2022)

The Original BMW expansion tank to cylinder head pipe is the coolant line that connects the engine's cooling system to the coolant reservoir on 2016–2022 BMW 5 Series, 6 Series Gran Turismo, and 7 Series models. When the engine heats up and the coolant expands, this hose carries the excess into the reservoir. When the engine cools down, it lets coolant flow back so the system holds the correct level. A leak at this pipe lets coolant escape from the overflow circuit, and the lost coolant can lead to overheating. BMW's parts data gives a weight of 77 grams and shows production of this number beginning in July 2015. The pipe is made in Germany and sold as a single piece.

Original BMW Parts carry a 24-month parts warranty.

This pipe belongs to the overflow side of the cooling system rather than the main radiator circuit. BMW uses one part number for it across several engine families. On these cars that covers the B46 and B48 four-cylinder engines in the 530i, the B48X plug-in hybrid drivetrain in the 530e and 740e xDrive, and the B58 six-cylinder in the 540i, 640i Gran Turismo, and 740i. BMW also carries the same number onto the later B58C engine, so a 740i built before or after the 7 Series facelift takes the identical pipe.

Technical Details

• Manufacturer: BMW (Genuine BMW)
• Part number: 17-12-8-602-612
• BMW part name: expansion tank to cylinder head pipe
• Function: carries coolant between the cooling system and the expansion tank
• Weight: 77 g (0.2 lb)
• Production start: July 2015
• Country of manufacture: Germany
• Sold as: one piece
• Warranty: 24 months on Original BMW Parts

Common Questions

What are the warning signs of a failing coolant overflow pipe?
Coolant leaks around the hose or reservoir, engine overheating, and a check engine light tied to coolant temperature or level monitoring can all point to this pipe.

Do the 530e and the 540i use the same pipe?
Yes. BMW uses this one part number for both the B48X hybrid engine in the 530e and the B58 six-cylinder in the 540i.

Does a facelift 740i take a different pipe?
No. BMW carries this number onto the B58C engine in the facelift G11 and G12 7 Series, so earlier and later 740i models share it.

Fitment & Compatibility

Use the fitment table below to confirm year, model, submodel, and application notes before ordering. With over 20 years of parts and fitment experience, PMB Performance can match this to your VIN.