Updated at: 18-03-2022 - By: micdot

Affiliate links can be found throughout this piece. There is no additional cost to you, and I may receive a small compensation if you make a purchase after clicking on one of my links. If you’ve ever driven and noticed that your car’s temperature gauge fluctuates erratically, you’re not alone. When the gauge rises, but the car isn’t overheating, it becomes more of a concern. When the car is not in use, the gauge can rise even when it is idling. Your car’s health should be on your mind after reading this.

We’ll cover a wide range of topics related to the temperature gauge’s erratic behavior in this post. You may have a faulty radiator or temperature gauge, which is causing the problems you’re having. Let’s get into the nitty-gritty here.

Why Car Temperature Gauge Goes Up And Down While Driving

Only when the automobile is overheating is the temperature gauge predicted to increase to the “red” zone. Assuming your automobile isn’t overheating, a reading in the red zone on the gauge means something’s wrong. You can tell something is wrong if the meter goes up when you stop the automobile. However, you should be aware that cars can overheat when idling, and this can be due to a broken radiator fan or other plausible causes. However, the primary cause of your car’s temperature fluctuation when driving is due to a flaw in the vehicle. What may have caused the problem? We’ll see what happens.

Why Car Temperature Gauge Goes Up And Down and No Heat

Consider them to be the most important contributing variables to the problem at hand.

1. Bad Thermostat Valve

Almost all of a vehicle’s components have the potential to fail and cause a breakdown. Accidents and/or crashes may be to blame, as may an ongoing high temperature. Even if your thermostat doesn’t have one of these problems, it’s still possible that it will degrade over time. When a thermostat malfunctions, it might be trapped in one of three positions: open, closed, or halfway open. Because of this, it doesn’t really matter how bad things became, as long as the engine overheats while driving.

The temperature indicator appears to climb when the engine begins to overheat. Your temperature gauge will rise and fall as you drive if the thermostat is faulty (maybe by opening or closing when it shouldn’t).

2. Faulty Cooling System

The cooling system is another common cause of the temperature gauge going up and down and no heat. In keeping with the name, this is a system that works to keep your automobile cool. There aren’t many complex systems in a car, but the cooling system is one of the most critical. A defective cooling system could be the cause of this if your car’s coolant reservoir is full. If this is the case, you’ll need to inspect the system for damaged or blocked components. You should seek the assistance of a professional if you are unable to identify these parts on your own.

Why Car Temperature Gauge Goes Up When Idle

Stop-and-go traffic or idling might cause your car to overheat, and these variables could be to blame.

3. Radiator Issues

When it comes to temperature control, a radiator is one of the most important parts of a modern car. It is made up of a variety of parts, including fans. The primary function of an automobile radiator is to cool the engine and prevent overheating by circulating air. It’s possible that defective radiator fans are to blame if you see your car’s temperature rising even when it’s sitting still. You can count on the air in the engine compartment to keep it cool as you drive, which explains why your car’s thermometer shows a reading in the normal/green range. Stopping the automobile might cause the engine to overheat and the temperature gauge to climb if enough air isn’t pumped into the engine bay. As you drive and encounter traffic or stops, the temperature gauge may continue to increase and decrease.

That being stated, it is possible that a broken radiator fan or the entire radiator system is to blame for your car temperature gauge rising while it is idling away. For troubleshooting purposes, you can inspect the radiator fans by following this procedure. Make a safe stop, turn off the car, and walk away. Do not touch the bonnet until it has cooled (if you have traveled long distances). This will protect your hand from being burned. Check your coolant level by opening the hood and adding more if necessary.

As long as the hood is still open, you can check the radiator fan without shutting off the engine. A malfunctioning radiator fan is likely to blame; if it’s still spinning, it’s likely to have been a contributing factor. The problem is that if you leave the ignition on for too long, you could damage the engine. You should only trust a certified/respected mechanic to fix your radiator if it fails.

4. Coolant Issues

There is a chance that the coolant could be to blame for this issue. Overheating can occur if the coolant level falls below the required amount. As a result, overheating can occur if the coolant is leaking, as well. A rise in temperature can be caused by a malfunction in the coolant in your vehicle. Even if your car’s cooling system is faulty, it is unlikely that your vehicle would overheat while you are driving due to the large amount of air that is pumped into the engine compartment as you accelerate. In order to keep cool after an exhausting ride, the car uses some of its own components and systems.

When your car’s coolant, thermostat, and radiator are all working together as they should, this is the time to pay attention. Engine temperatures can soar to dangerously high levels if any of these components fail to function properly while your automobile is idling. As a reminder, if the temperature gauge varies as you drive, it may not be a coolant problem. Even so, the coolant and its components must still be inspected (hoses). Before leaving the garage, be sure to top off the coolant or antifreeze in your automobile. Always check for coolant leaks, and fix them if you find them.

Why Car Temperature Gauge Rises Then Falls

Everything that has been discussed thus far can cause your automobile temperature gauge to malfunction. In addition, the temperature gauge itself can become faulty and start to malfunction. That being said, it’s crucial to realize that different automobiles have varying temperature gauges. Having a faulty CTS can cause the temperature gauge to read inaccurately. The temperature gauge can malfunction for a variety of reasons, some of which may be to blame for the problems you’re experiencing.


Something is wrong with your car’s cooling system if your temperature gauge fluctuates while you’re driving. Radiator fans, water pumps, thermostat valves, coolant, or even the gauge itself, could be the source of the problem.. We recommend that you seek the services of a well-respected auto repair to resolve either of these problems. Also, make sure to keep up with your car’s maintenance and be proactive about any concerns that may arise.