Heavy duty thermostats regulate how much coolant is circulated back into your truck’s engine and how much is cooled through the radiator before it is redistributed. This process helps the coolant in your engine stay within a specified temperature range despite outside temperatures.FleetPride specializes in thermostat parts from quality-built brands. Our large assortment includes not only truck thermostats, but also thermostat gasket sealers, thermostat housing gaskets, and more. We have a diverse inventory, so you can be sure to find the right part for your heavy duty needs.FP Diesel is a leader in replacement engine and sealing components for the heavy duty truck industry. FP Diesel products thrive in demanding environments and offer a cost-effective solution for customers. FP Diesel was founded in 1993 and is a part of DRiV, Inc. Through strategic partnerships, they have gained capabilities to expand their product line. As a result, FP Diesel and DriV have seen positive growth around the globe.