Car Temperature Gauge Goes Up And Down While Driving

Every car model has a thermometer. This part is located on the control panel, so you can easily observe it. This meter is capable of determining the temperature inside the engine and how the cooling system is working. If the indicator exceeds the red line, it is signaling that your machine is overloaded.

However, if you are usually driving and notice that the temperature gauge rises and falls abnormally, you need to be very attentive. So, what is the cause, and is there a way to fix this problem? Let’s find out a few reasons why the car temperature gauge goes up and down while driving and how to fix it effectively.

How The Car Temperature Gauge Works

In addition to the tachometer system, the thermometer is also one of the car’s most essential parts. They will help you determine the exact temperature inside the engine and alert you when the part is overloaded.

Specifically, this meter has the same design as the tachometer system. The line near the letter “C” means the temperature is in the cold range. 

A reading near the letter “H” means that the heat is a bit high, and you need to release it. It would help if you did not let the line touch the red level because this is a dangerous level that affects the engine.

In addition, there are some high-end cars such as bentleys that will have an electronic car temperature gauge. The system will accurately display the engine’s internal temperature, making it easier for you to observe.

Reason For Car Temperature Gauge Goes Up And Down While Driving

Car Temperature Gauge Goes Up And Down While Driving

Car temperature gauge going up and down is a sign that needs attention. Here are 5 reasons why the system behaves abnormally:

Motor overload.

Motor overload is a pretty obvious cause. When you drive long distances, the parts will have to work continuously and give off a large amount of heat. If you regularly use the car in such a state, the engine’s life will be reduced.

Not only that, when the heat level is too great, in the long run, the cylinder head will be bent. This incident is quite dangerous and seriously affects the quality of your car.

Another mistake is that you increase the speed suddenly. When you short press the gas to reach maximum speed, the engine will not have time to adapt and must generate a large amount of heat to maintain itself. At that time, the thermometer will touch the red line because the temperature is too high.

The thermostat has a problem.

The primary function of the thermostatic valve is to regulate the temperature inside the engine. When it senses the car is hot, it adjusts the incoming coolant to reduce the amount of heat inside. From there, your vehicle will always be in top condition.

A car thermostat last is usually relatively short, so you will have to replace it often. However, what if you do not find out that this part is having problems?

The thermostatic valve will prevent the cooling system from being transmitted to the engine, causing overload. At that time, the thermometer will approach the letter “H.” If you do not replace it in time, the quality of the car engine will significantly decrease.

The radiator fan is not working.

Another part that will also affect the temperature inside the engine is the radiator fan. The fan has the role of drawing air from the outside when the car is running to reduce heat. This unit is located right next to the cooling system to enhance the ability to regulate the temperature.

However, if the radiator fan works abnormally, it will lead to motor overload. The amount of outside air is not enough to reduce the temperature inside. From there, the car temperature gauge will increase to signal to you.

Faulty cooling system.

It can be that coolant is one of the most critical systems to keep the car’s temperature at a reasonable level. But it is also this part that will significantly affect the engine if they are faulty.

Specifically, when the cooling system is not working, the water pump cannot transfer coolant to the inside of the engine, which will lead to high motor temperature and overload. 

You can easily recognize this phenomenon when your car has difficulty starting or moving.

Faulty electronic devices.

One cause lies not in the internals but in the car temperature gauge itself. All electronic devices cannot be maintained forever. Therefore, experts often recommend that you keep your car according to the instructions to repair the parts having problems promptly.

If you have checked all the components and found no problems, the heat meter may be blamed. Since this part is a modern electronic device, it is not recommended that you repair it yourself at home, but seek out your local professional auto repair shop and ask for their help.

How To Troubleshoot Effectively

After determining the cause of the problem, you need to make repairs in time to keep the quality of the car in better condition:

Replace thermostatic valve.

The replacement will require a lot of tools and understanding. If you are not car savvy, your best bet is to drive your car to a repair center. If you have basic knowledge about cars, you can refer to the following steps:

  • Turn off the engine and wait for the car to cool down for about 30 minutes.
  • Prepare tools: screwdriver, gloves, wrench, hammer, vise clamp, and of course, a new thermostatic valve.
  • Locate this part.
  • Remove the radiator valve caps and drain them.
  • Install the new product in the correct position.
  • Close the valve and do a final check.

Change the cooling system.

Replacing the cooling system is also quite similar to the steps to replace the thermostat valve. The method is only slightly different in that you need to examine it more closely. You can follow these steps:

  • Leave the car idle for 30 minutes.
  • Determine the location of the system.
  • Open the cover of the cooling system.
  • Drain all coolant inside the radiator.
  • Remove all problematic parts.
  • Install a new cooling system.
  • Connect the internal terminals to the motor.
  • Check the system and car temperature gauge.


A car temperature gauge is capable of informing you what the internal temperature of the engine is. If this part works abnormally, you need to find the cause and deal with it quickly because they are signs of internal devices having problems.

Timely detection and finding ways to repair it will help prolong the life of your car. You should regularly maintain your vehicle to improve product quality. Hope the above article has helped you find the cause of the car temperature gauge going up and down while driving and how to fix it effectively.

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