Water hose from expansion tank to auxiliary water pump on on 1999-2003 E39 525i, 528i, 530i.
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, leaving you with the potential for loss of control from coolant spilling and/or an overheating situation. Replace your radiator hoses as a preventative measure before they fail in order to save you from further headaches and expenses. 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 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.
E39 (97-03) > 525i
E39 (97-03) > 528i 97-98
E39 (97-03) > 528i 99-00
E39 (97-03) > 530i