Idler Deflection Pulley, Upper - E82 135i, E9X 335i, E60 535i, Z4 35i (N54)
OEM upper 80mm deflection pulley
The N54 has two deflection pulleys - this is the upper pulley located next to the tensioner. 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. A new mounting bolt is included.
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.
E82 / E88 (08-13) > 135i
E82 / E88 (08-13) > 1M (11-12)
E90 / E91 / E92 / E93 (06-13) > 335i
E90 / E91 / E92 / E93 (06-13) > 335is
E90 / E91 / E92 / E93 (06-13) > 335xi
E60 / E61 (04-10) > 535i
E60 / E61 (04-10) > 535xi
E89 Z4 (2009-2016) > Z4 sDrive35i
E89 Z4 (2009-2016) > Z4 sDrive35is