When driving, you might get concerned when the car temperature gauge goes up and down. It gets you even more confused when you check your car and realize it is not overheating.
If you face this challenge, you should understand that a couple of circumstances cause your car’s temperature gauge to go up and down.
You should note that the main challenge is in your vehicle’s cooling system. Maybe there might be bad wiring, or you’re the temperature gauge is worn out. Also, it might be a result of a faulty coolant temperature sensor.
Therefore, as a car owner, you need to narrow down what causes the car temperature gauge to go up and down while driving.
This article will help you learn why your car temperature gauge fluctuates while driving and how you can fix the problem.
Car Temperature Gauge Goes Up and Down While Driving Causes and Fixes
When the car overheats, the temperature gauge should only go up to the “red” zone
However, there must be a problem if the temperature gauge rises to the “red” zone without your car overheating. At the same time, if the car temperature gauge rises when the car stops, then there is an issue.
Therefore, there has to be a problem if your car temperature gauge goes up and down while driving.
Below are the common causes of temperature gauge fluctuation and how to fix them.
1. A Faulty Thermostat
When the thermostat has a fault, it remains open permanently, stuck halfway, or completely closed.
Regardless of how the problem happened, a faulty thermostat will make the engine overheat.
Since the car’s thermostat controls the temperature of the engine’s coolant, if there is a fault in the thermostat valve, you will likely get inconsistent numbers on your thermometer.
A fault in the thermostat valve will make your car overheat. You can still drive with the issue for a certain period before getting your car repaired. However, if the thermostat fluctuates at once, your engine has a more serious problem.
Fixing: Take your car to the mechanic for changing your thermostat
2. A Malfunctioning Water Pump
If your temperature gauge goes up and down consistently, you will likely have a faulty water pump or a bad radiator cap.
If there is damage to your water pump, it will continuously make your car overheat.
Therefore, have someone check your car to see exactly where there is a problem.
The ignition switch that controls the power received by your temperature gauge should be checked. If still, you don’t get where the exact problem is, check the sensors manually.
Fixing: The repairer should check the sensors for the cooling system and the overheating system. If either sensor has an issue with the reading, it should be replaced immediately.
3. A Bad Radiator
A radiator helps circulate air within the engine bay to cool it down and ensure no overheating.
A fault in the radiator will make you experience a temperature gauge going up and down while in traffic or idling.
If you notice any issue with the radiator, you should change it immediately. Failure to change the radiator causes the color of your coolant to change from yellow to rusty hence unable to cool the engine down.
Another cause for temperature going up when the car is idling or in traffic is a bad radiator cap. Air penetrates the radiator if not sealed properly and results in the radiator hoses and heater core; hence the engine overheats due to lack of stable temperatures of the coolant in the entire engine.
Fixing: Please note that leaving the ignition for a long time can negatively impact the engine. If your radiator fails, get a certified mechanic to fix it; don’t let just anybody handle it. Also, replace the radiator and the fan immediately.
4. Defective Computer Module
A computer module helps ensure communication between the car’s engine and other computer modules. Thus, it is responsible for driving the temperature gauge on your car’s dashboard.
If your engine is very hot and the temperature gauge does not go up and down, there is a problem with the computer module.
If you notice this problem, do not ignore it since it can lead to other damages, which can be very costly compared to a new computer module.
Fixing: Get a certified technician to scan all your car’s systems to determine an issue with the computer module. If the scan shows something is wrong, take your car to someone who can fix the complicated machine or replace your computer module.
5. Low Water in the Cooling System
Engine coolant is an essential fluid in maintaining the optimum temperature levels.
If your engine lacks enough water for cooling, the temperature goes up to unsafe levels and makes the car overheat.
Coolant is responsible for releasing heat from the engine to allow the radiator to pump the heat safely outside. When there is no adequate water for cooling, the heat gets lost, hence overheating.
Fixing: If your engine constantly overheats, replace the coolant immediately to ensure the cooling system and the radiator works efficiently.
6. Trapped Air in the Cooling System
If you take your car out, sit in traffic for an hour or more, and upon checking the temperature gauge has gone down, there is air trapped in the cooling system.
Fixing: If you can’t figure out exactly where the air is trapped, take it to a mechanic for full inspection. Ensure the problem is fixed immediately to avoid further damages and expenses in the future.
7. A Faulty Temperature Gauge
It is important to check the temperature gauge itself.
A damaged sensor can mess your temperature gauge, so it’s important to check it out. In addition, check all your connections to ensure nothing is flapping in the breeze. Loose connections can cause overheating due to added friction.
Fixing: Get a qualified person to check your car; only them can identify and help repair the problem of your temperature gauge.
On Car Temperature Gauge Goes Up and Down While Driving
The temperature gauge goes rises and falls depending on the surrounding temperature.
If your car’s temperature gauge goes up and down while driving and does not go back to normal, there is a problem with the cooling system or the radiator.
Therefore, if you notice the fluctuation consistently, don’t ignore it. It would be best to get a mechanic to check your car and replace any defective components immediately before they cause more damage to the engine.
Hi I’m Marshall based in 1478 Doctors Drive Santa Monica, CA. I’m your DIY Car Repairman with more than 5 years experience in automobile repair, a skill I learned from my old man.
I started this blog to share my experience on both simple and technical aspects of your car.