The original coolant thermostat housing assembly on certain Chrysler, Dodge, Jeep, Ram and Volkswagen vehicles is made from plastic that becomes brittle over time, eventually leading to cracks. In addition, overtightening the bleeder valve can cause fluid leaks that can damage the cooling system. This Dorman OE FIX thermostat housing assembly is manufactured from corrosion-resistant aluminum to help provide increased cooling system protection, and features patented design upgrades that optimize coolant flow and heat transfer.