5 Not So Common Reasons Temp Gauge Goes Up and Down While Driving

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Temp Gauge Goes Up and Down While Driving

If you notice your temperature gauge on your dashboard fluctuates up and down while driving, it’s likely an issue with the car. Before heading to a mechanic, let’s see what causes the temp gauge goes up and down while driving and is there anything you can do about it.

What Is Temperature Gauge?

A temperature gauge is an instrument attached to the dashboard of your vehicle. It measures the amount of heat emanating from the engine.

Now, why do you need to know the temp gauge inside your vehicle? It is because coolant fluid keeps your vehicle engine running cool and comfortable. If your engine begins to overheat, then steam is released into the air that can be dangerous for you and everyone else who gets close to it.

What Causes Temp Gauge Goes Up and Down While Driving

Let’s see why the temp gauge goes up and down while driving.

1. Control Valve

Your engine has a control valve that regulates the amount of coolant it allows into the engine. These components can become worn out over time and need to be replaced. If the control valve is weak, then it can leak without you even noticing. In this case, you’ll see steam coming from the cooling system of your vehicle since there is no coolant in there to keep it from overheating.

2. Thermostat

The thermostat is responsible for regulating the temperature of the engine. It controls the amount of coolant that enters the cylinder and keeps it from overheating. If your thermostat becomes worn out, then it may start to leak and block your cooling system. When this happens, you’ll start seeing steam coming from your engine internals since there’s no way to get coolant into them anymore. The only fix for this is a new thermostat and replacement of other related components that rely on it.

3. Overheating Engine

A vehicle’s engine can overheat because there’s something wrong with it. The coolant can be affected by other parts that are worn out or there could be a problem with the thermostat. At this point, you’ll need to pay for a replacement for the entire engine instead of just dealing with your temperature gauge going up and down while driving.

4. Radiator Issues

The radiator aims to keep your vehicle cool by producing coolant. It can be blocked by debris or not properly secured, which will cause it to leak and put the entire engine at risk of overheating. If any of its components are at fault, they can cause the temp gauge to fluctuate as well.

  • Radiator Cap: Your radiator has a cap that regulates the amount of coolant inside it. If this cap is weak, then it may come loose and cause your temperature gauge to fluctuate.
  • Faulty Radiator Fans: The fans inside your radiator are responsible for spreading the coolant throughout the engine. If they are faulty or not working, then it can cause your temperature gauge to go up and down while driving.
  • Faulty Radiator Hoses: There are several hoses connected to the radiator that are responsible for carrying coolant toward the engine properly. If one of these hoses becomes weak or damaged, then your temperature gauge is likely to go up and down when you drive.

5. Not Enough Coolant Liquid

Your engine needs a certain amount of coolant liquid to run comfortably. If there’s not enough coolant in the radiator, then the engine will overheat and your temp gauge will show erratic numbers on the dash.

6. Faulty Water Pump

The water pump is responsible for circulating coolant through the engine. If it fails, then the coolant will not reach the engine. This can cause your temp gauge to go up and down while driving.

What You Can Do About It

If you see your temperature gauge going up and down while driving, then the first thing that you should do is take your vehicle to a mechanic. Let them check to see what’s wrong with it. They’ll be able to replace the parts that are broken or worn out or determine if you need a new engine or not.


Never forget to give your engine a good check-up every now and then. In the event that you notice the temp gauge going up and down while driving, make sure to take your car to a mechanic immediately. It is better to be safe than sorry!