Why Do Diesel Engines Have Two Thermostats?

Most trucks and farming equipment have been using dual thermostats recently. Generally, they have two thermostats because they serve different purposes from each other.

The front one is to control the coolant flow from the bypass port to the outlet, while the rear thermostat only helps keep the water outlet cool.

This article covers why diesel engines have two different thermostats and their purposes. So, continue reading.

What’s a Thermostat?

Why Do Diesel Engines Have Two Thermostats

A thermostat controls the coolant that circulates throughout your engine. It is used to correct the engine’s temperature to its correct operating level.

When heated, the wax-pellet element expands and signals the valve to open through a piston connected to it. 

After the temperature goes back to its normal operating heat, the pellet then contracts, closing the valve and trapping the coolant again.

Cooling System Of An Engine

YouTube video

This video starts off with the speaker describing how a typical car engine works. This would lead to easy heating of the whole engine, and the cooling components are introduced. These include:

  • Water Pump
  • Radiator
  • Thermostat
  • Coolant Temperature Sensor
  • Coolant

The video discusses these parts individually, but the thermostat is the one that regulates when the coolant flows in and out of the engine to maintain its proper operating temperature.

Finally, the video shows how all of the parts work together to maintain the proper temperature for the engine.

Frequently Asked Questions

Is a thermostat absolutely necessary to run a diesel engine?

The direct answer to the question is yes. It would be very difficult to restrain the flow of fluids in a diesel engine without a thermostat.

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In a very hot environment, the engine needs more power since it would run a lot hotter than it’s used to. A thermostat will help the engine determine if it has to work at a different pace than normal. 

Additionally, there would be less demand for fuel for the engine in a hot environment. It would also result in less wear and tear inside the diesel engine if run in hotter environments.

How does the thermostat work inside your car?

A thermostat is a kind of like a signal that your car reads when it reaches certain temperatures.

For example, in a humid environment, the thermostat sensor would swell, making the thermostat valve open because it is all linked together in one set piece. 

With the opening of the thermostat valve due to the temperature sensor swelling, cooling then comes and takes its place.

It would go and cool around the components in order for the engine to avoid overheating and getting damaged when driving.

What happens if you don’t have a thermostat?

Even without a thermostat, your vehicle would have its own homeostatic cooling system flowing throughout the engine.

If the engine had its thermostat installed improperly, then there would be problems with exactly knowing when the cooling system should be activated and when it should be turned off. 

Will the engine overheat without a thermostat?

Yes, it will. The lack of a thermostat could result in overheating because the coolant passes through too fast around the engine.

This would result in some cases absorbing more heat than necessary from the engine, which would result in possibly more wear and tear inside your engine.

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