Deflection/Idler Pulley, OEM - N55 F22 F30 F32 X3 X4 X5 X6 35i, S55 M2/M3/M4 - 11288673720

The N55/S55 deflection, or idler, pulley is located separate from the tensioner pulley and guides the belt around other accessories. The pulley contains a set of bearings, that when worn, will produce a screeching or rumbling sound. It's important to inspect and replace the pulley regularly. Spin the pulley by hand and listen for grinding or rumbling sounds and if there is resistance. All of these are signs of bad bearings. The pulley wheel is made of plastic and they are known to crack and snap and get flung around the engine compartment. They can damage your radiator, hoses, fan, and other critical items that will lead to a more expansive/expensive repair. Since the deflection pulley is bolted in place, not pressed on, it is easily replaced during a routine belt change.

NOT for the earlier N54 twin turbo engine cars. For cars with the N55 "TwinPower" engine and S55 M engine. If your BMW is a pre-2011 model, this is likely not the style belt idler / roller pulley you need. 

This pulley is manufactured by INA, the original supplier to BMW for this part and other pulleys. Since it is an OEM part, it conforms to the original design that BMW specified for the engines listed above. It comes with a two year warranty.