Belt Tensioner, INA - F22, F30, F32, X3, X4, X5, X6 35i, M2, M3, M4 - 11288604266

This is the mechanical belt tensioner used on 2011-2016 N55 - F22 M235i, F30/F34 335i, F32/F33/F36 435i, F10 535i, F13 640i, X3, X4, X5, X6 35i, as well as the F87 M2, F80 M3, and F82 M4. 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.

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

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 N55 engine. It comes with a two year warranty.