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.
Replaces BMW part # 11287556251 (11-28-7-556-251).
BMW Fitments:
1 Series
E82 / E88 (08-13) > 135i N54 (08-10)
E82 / E88 (08-13) > 1M (11-12)
3 Series
E90 / E91 / E92 / E93 (06-13) > 335i N54 (07-10)
E90 / E91 / E92 / E93 (06-13) > 335is N54
E90 / E91 / E92 / E93 (06-13) > 335xi N54 (07-10)
5 Series
E60 / E61 (04-10) > 535i
E60 / E61 (04-10) > 535xi
Z Series
E89 Z4 (2009-2016) > Z4 sDrive35i
E89 Z4 (2009-2016) > Z4 sDrive35is