Coolant Overflow Tank Recovery Bottle Expansion Reservoir Replacement for BMW 3 Series X3 X5 17117573781 High quality reservoir to hold excess cooling agent to help keep your engine running smooth Affordable, superior aftermarket coolant tank for your BMW E46 3 Series & X3 E83 X5 E53 3.0L Engineered to stand up against the stresses of heat and vibration preventing cracks or leaks OE Style: Premium plastic and design ensures a dependable, precise fit and function No Modification needed and protected by 1 year limited warranty