This is the proper expansion tank hose on E53 X5 4.4/4.6is. Having the proper hose is crucial to cooling system performance. A non-stock or generic hose may not have the same length or shape and could diminish cooling or fail to fix annoying leaks.
This is a expansion tank hose manufactured by Rein (CRP) Automotive - the original supplier to BMW for this part, as well as many other hoses. As the OEM it meets all of BMW's original design, fitment, and performance requirements and is TUV approved. OEM parts are the best alternative to more expensive Original BMW parts because they are virtually identical without the inflated price tag. This part has a two year warranty.
E53 X5 (00-06) > X5 4.4i M62 (99-03)
E53 X5 (00-06) > X5 4.6is M62