Expansion Tank Hose, BMW - G01 X3, G02 X4 30i B46 (2018-2019)

This part is listed by BMW as BMW part number 17127535536 (17-12-7-535-536) and is described as the coolant hose connecting the coolant reservoir to the auxiliary water pump and thermostat module on 2018-2019 G01 X3 30i and G02 X4 30i (with the B46A engine).

This is a complicated hose that serves three components in the X3/X4 cooling system. It's the drain hose for the coolant reservoir and supplies coolant to the small auxiliary water pump and to the thermostat module.

Rubber hoses are ideal when new, as they allow some movement and flexibility during driving. The only problem is that they begin to degrade as they age and can eventually fail. The plastic clips and metal retaining clamps on hoses are stronger than before but they are only really good for one-time use. Once removed they never seem to seal as well, leading to a leak soon after. A new hose is recommended any time the old one is disconnected (unless it's only a couple of years old). We highly recommend that you replace your cooling system hoses as a preventative measure before they fail in order to save you from further headaches and expenses.

This is a Genuine BMW X3 coolant hose with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.

For full BMW fitment information or for assistance from one of our BMW experts, we recommend calling us at 877-639-9648.