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While your Duramax thermostats are one of the cheapest parts on your diesel engine, they can cause the most damage when not functioning properly. A non-functioning thermostat can cause your coolant to not flow through your engine, leading to overheating issues. Left unattended, this can lead to blown head gaskets or other major engine damage. Don’t let a malfunctioning thermostat harm your engine, get a direct replacement Duramax thermostat from Merchant Automotive.

The thermostat on your engine resides in a thermostat housing that is installed in line with your cooling system. The thermostat is closed until the engine reaches operating temperature. Once your engine reaches operating temperature, your thermostat opens, allowing coolant to flow through your engine to maintain the operating temperature for maximum engine efficiency.

Why Does A Duramax Have Two Thermostats?

Unlike gasoline engines, the Duramax diesel engine has two thermostats in it’s cooling system. This is designed to accomplish the same temperature control under different load conditions. For times where your truck is used under light load conditions, only the primary thermostat stays open. Once you are using your Duramax for heavier load towing, your secondary thermostat will open to achieve maximum cooling efficiency.

What Are The Signs Of A Bad Duramax Thermostat?

When it comes to a bad Duramax thermostat, there are two different scenarios that you can run into. The first being that your thermostat is stuck open and the second being that your thermostat is stuck closed.

A thermostat that is stuck open will not allow your engine to reach operating temperature as coolant will always be flowing through your engine. Your Duramax will not have a chance to reach operating temperature due to coolant constantly flowing through the engine block.

A thermostat that is stuck closed can quickly overheat an engine as your coolant will not have the chance to flow through your engine block. The thermostat being stuck closed will cause a blockage in your cooling system which will cause your engine temperatures to rise.

What Temperature Should A Duramax Run?

Most Duramax diesel engines are going to run at a temperature of 210 after it has warmed up and the thermostat has opened. If your Duramax runs hotter or colder than 210, you may have a thermostat that has failed or an aftermarket thermostat that is designed to run hotter or colder. To ensure you have the proper temperature, check your owners manual for your truck to verify what your engine should be running at.