Thermostats & Housing

The thermostat controls when coolant flows to the radiator, which keeps the engine at its proper operating temperature. A thermostat stuck closed causes overheating, while one stuck open keeps the engine running cold, which hurts fuel economy, heater performance and, on modern diesels, emissions system operation.

Shop thermostats for Cummins, Duramax, Power Stroke and other engines from Gates, Mishimoto, Alliant Power and others, sorted by engine family. We also carry thermostat housings and necks from Wehrli, PPE, Mishimoto, Moroso and Fleece, including billet aluminum housings that replace factory plastic or cast parts known to crack or leak.

Diesels need to reach full operating temperature to run cleanly and regenerate their emissions systems, so stick with the factory-rated thermostat unless you have a specific reason to change it. When replacing a thermostat, always use a new gasket or seal, and bleed the air out of the cooling system after refilling. Trapped air can cause hot spots and false temperature readings.