Thermostat Problems – Will Affect Your Engines Performance

Thermostat Problems - Will Affect Your Engines Performance
Thermostat Problems - Will Affect Your Engines Performance

The thermostat is a simple valve that opens and closes in relation to engine coolant temperature.

So, Almost all thermostat problems will have some effect on your engine performance.

As we already know, the main purpose of the thermostat is to maintain the engine at the proper operating temperature.

All thermostat problems will have some affect on your engines performance

The thermostat starts at a closed position when you start the engine to help it reach operating temperature. While the engine is running the coolant temperature slowly rises, making the thermostat begin to open. The opening allows warmer coolant in the engine to flow into the radiator. In turn, The water pump pushes lower-temperature coolant from the radiator into the engine.

Thermostat Illustration
Thermostat Illustration

When the lower-temperature coolant reaches the thermostat, the warmer fluid begins to cool, closing the thermostat. During engine operation, the thermostat actually never fully closes or opens, but gradually nears either state to control coolant flow. This allows the engine to operate at a specific temperature controlled by the thermostat.

Thermostat problems will prevent your engine from operating within its ideal temperature range and affect its performance.

The engine has to reach a specified temperature before the computer will go into what is called closed loop mode. This is where the computer adjusts the fuel mixture from the signals it receives from the oxygen sensor.

Your engine must be allowed to run in closed loop mode.

So, If the engine doesn’t reach this specified temperature the computer won’t go into this closed loop mode. But instead stay in the open loop mode. So the computer will deliver more gas because the computer thinks the engine is still cold.

The Thermostat Has Two Important Functions:

  • To accelerate engine warm-up.
  • To regulate the engine’s operating temperature.
Thermostat Problems
Thermostat Problems

Having A Properly Working Thermostat Will:

  • Help fuel economy
  • Reduce engine wear
  • Diminishes emissions and blow-by
  • Improves cold weather drivability
  • Provides adequate heater output
  • Helps with overheating

Signs Of Thermostat Problems:

  • Higher Than Normal Engine Temperature
  • Lower Than Normal Engine Temperature
  • Fluctuating Engine Temperature (Changing Erratically)
  • Poor Engine Performance
  • Engine Takes A Long Time To Warm Up
  • Engine Overheating
  • Popping-Boiling Noises Coming From Your Heater

Most Thermostat Problems Happen In One Of Two Ways:

  1. If the thermostat becomes stuck in the open position, there is continuous flow of coolant into the radiator causing the engine to run cold. Overcooled engines run inefficiently, which leads to increased fuel consumption and higher emission levels and engine parts enduring more wear. In addition, the car interior will not heat up properly.
  2. If the thermostat becomes stuck in the closed position, the circulation of the coolant is blocked so the coolant cannot get to the radiator to be cooled which causes the engine to overheat.

The consequences of an “open failure” may be less catastrophic than those of a “closed failure”.

If your engine has overheated for any reason, Replace your thermostat. Thermostats are cheap and can be purchased at your local auto parts store.

So, How Can New Technology Improve The Basic Thermostat

Read Our Post On Electronic MAP-Controlled Thermostats


So, Vehicle manufacturers are under intense pressure to produce cars and trucks that produce fewer emissions. Closely regulating the cooling system is one way to do that. Finally, By achieving finer control of existing systems and using different techniques to regulate temperatures.

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