Thermostat Problems Will Affect Your Engines Performance


Thermostat in proper working order:

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.

Thermostat problems usually happen without any warning.

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, the expanding fluid begins to contract, 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 the best temperature.

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

Your car begins to overheat soon after you start it up, or the temperature gauge remains below normal.

The thermostat has two important functions:

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

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.

If your engine has overheated for any reason, Replace your thermostat. Thermostats are cheap and can be purchased at your local auto parts store. Remember to keep up with regular maintenance to avoid contaminated coolant. Too little or no antifreeze can cause rust and damage.

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

  • A thermostat stuck open will cause a continuous flow of coolant, resulting in a lower operating temperature. Since the oil operates below temperature, the condition accelerates wear, reducing engine efficiency and increasing emissions.
  • On the other hand, a thermostat stuck in the closed position will prevent coolant flow and cause the temperature to steadily rise. Consequently if you fail to notice and keep your engine running, in a matter of minutes your engine overheats.
Thermostat problems affect vehicle's performance
Thermostat problems affect vehicle’s performance

Thermostat problems are not the only cause for an abnormal engine operating temperature.

Abnormal engine temperature causes can also be;

  • Bad thermostat
  • Low coolant level
  • Collapsed radiator hose
  • Bad radiator fan
  • Clogged radiator
  • Cooling system leaks
  • Loose water pump belt
  • Worn-out water pump belt
  • Bad water pump
  • Rad cap


A bad thermostat can cause the car to overheat. When the temperature of the engine reaches its normal operating temperature, this device should open to allow coolant to flow into the engine to regulate the heat. Hence if the thermostat is stuck closed, antifreeze will not flow from the radiator, resulting in the car overheating.

Under Heating

If the thermostat is stuck open, it will lead to engine under heating. The open setting means that coolant will be constantly moving into the engine, regardless of whether it is hot enough to need it. Instead of ending up too hot all the time, the engine will then have an issue with being too cool.

If you have been driving for a few minutes and your vehicle’s temperature gauge needle is still sitting close to the bottom, it’s time to check your thermostat.

Temperature Fluctuations

Thermostat problems will result in odd temperature fluctuations. In this case, the thermostat will not be stuck in any one position, but there will still be false readings causing problems with regulation. The engine temperature will change erratically while the radiator coolant is prohibited from flowing normally.

Poor Engine Performance

If the engine’s operating temperature is all over the place while trying to function, engine performance will ultimately suffer. This will lead to reduced gas mileage and, eventually, damage to your engine.

Furthermore some newer cars do not come equipped with an engine temperature gauge, only a warning light. When the warning light comes on in these cars, find a safe place and turn off your car immediately. Your vehicle is already overheating.