What Does A Thermostat do?

It’s cold out, but it’s always sunny and 65 at Trinity Auto Care. It’s so cold in fact that this thermostat (out of a 2005 Jeep Commander with a 5.7L Hemi engine) developed a crack and then came apart. Let’s figure out why.

The thermostat in your vehicle regulates the temperature in the engine by controlling coolant flow. The coolant in your vehicle removes heat from the engine by flowing through the passages within the engine block, coolant hoses, and then through the radiator and heater core in your vehicle. The water pump keeps the coolant flowing.

This thermostat actually froze to the point that the bottom of it cracked and the secondary disc valve came off.

How does a thermostat work?

The thermostat starts at a closed position when you start the engine to help it reach operating temperature. As coolant temperature rises, it begins to open. The opening allows hot coolant in the engine to flow into the radiator, while the water pump pushes lower-temperature coolant from the radiator into the engine. When the lower-temperature coolant reaches the thermostat container, the expanding fluid begins to contract, closing the thermostat’s valve.

When a thermostat fails in the closed position, your vehicle runs hot and can overheat. Overheating can lead to major issues down the line.

When it fails in the open position, your vehicle will run cold and inefficiently. It will take a long time for your vehicles heat to start working.

Servicing your cooling/antifreeze system regularly and making sure your antifreeze protection levels are high enough will help prevent a thermostat failure such as this. If your vehicle is experiencing poor heat or if the temperature gauge appears to be running hot, have your vehicle checked out at Trinity Auto Care today. We are White Bear Lake’s first choice for auto repair and maintenance.


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