Belt Tensioner, OEM INA - E82 128i, E9X 325i/328i/330i, E60 525i/528i/530i, X3, X5, Z4 (N51/N52)

This is the mechanical belt tensioner used on most 2006-2013 N51/N52 vehicles - E82 128i, E90 E92 E93 325i/328i/330i, E60 525i/528i/530i, X3, X5, and Z4. The tensioner keeps the main accessory belt at the proper tension for driving the accessories - alternator, power steering pump, and A/C compressor. A failing tensioner will allow the belt to loosen or slip resulting in diminished performance, especially from the alternator. In extreme cases the belt can slip off the pulleys and potentially lead to a catastrophic engine failure (rare but documented). As a preventative maintenance plan, we recommend replacing the tensioner at every belt change, or 40-60,000 miles. The extent of damage from a failed belt is worth the extra cost every few years.

This tensioner includes the roller pulley. The Torx mounting bolt cannot be reused and must be ordered separately.

This tensioner is manufactured by INA, the original supplier to BMW for this part and other engine components. Since it is an OEM part, it conforms to the original design that BMW specified for the N51/N52 engine. It comes with a two year warranty.