20851217 Automatic Serpentine Belt Tensioner For Mack E7 MP7

This premium 20851217 automatic drive belt tensioner assembly is built strictly to OEM standards, compatible with Mack CH, CX, Granite series trucks equipped with E7, MP7 diesel engines, interchangeable with 87GB41, 87GB41A, 87GB41B, 87GB41C, it adopts high‑strength cast‑aluminum housing and permanently sealed lubricated bearing pulley to maintain stable belt tension, effectively absorb engine vibration, prevent belt slipping, squealing and premature wear, ensures reliable operation of alternator, water pump and air‑conditioning system, simple bolt‑on installation without extra modification, ideal aftermarket replacement for fleet maintenance to cut downtime and extend accessory drive system service life.