Your engine must operate within a specific temperature range. This is the job of your cooling system, which keeps the engine running safely and efficiently regardless of weather and road conditions. It also communicates with the driver, providing her or him with the engine temperature as long as the engine is running. For this purpose, it uses the temperature gauge on the dashboard. It continually sends temperature readings to the gauge, which converts them into numbers or a movement of the needle.
The engine cooling system relies on the temperature sensor submerged into the coolant to read its temperature. Depending on the coolant temperature, the sensor sends different signals to the temperature gauge directly or to the engine control unit, which then causes the temperature gauge needle to move. The latter is the most common way of engine temperature control in a modern vehicle. If your vehicle was produced in 1996 or later, it is also equipped with a computer-controlled temperature sensor.
Your temperature gauge is one of the most important indicators found on your dashboard. It keeps you aware of how hot or cold the engine is running and allows you to prevent severe damage to the engine and cooling system components. Your gauge should feature a special temperature scale with hot and cold marks on its ends. In an ideal world, its needle must be in the center of the scale, which corresponds to the optimum engine temperature. In reality, your gauge can provide slightly higher than normal readings if you drive in a hot climate, towing something or your air conditioner is running at its full. However, the needle should never reach the red (hot) zone if the cooling system operates properly.
If you notice high readings on the temperature gauge, you can do a couple of things which may help you to prevent the engine from overheating. You can turn off the air conditioner and turn on the heater to reduce the coolant temperature. The heater acts as a second radiator, lowering the coolant temperature when the coolant flows through it. If it doesn’t help, shut down the engine and let it cool down to normal temperatures. In some cases you may also need to top up the coolant level.
What should I do if the temperature gauge provides high readings?
If your temperature gauge shows your engine is getting hotter, this means excessive heat is collected inside the cooling system due to some engine problems or cooling system problems. You may also notice illuminated warning lights on your dashboard and hear a warning chime. If this happens, you should stop the car and shut down the engine to prevent its overheating. Don’t try to open the hood once you have stopped the car as this may lead to a serious injury. It’s better to call your mechanic for advice and let the engine cool down.
High gauge readings and engine overheating can be caused by an array of problems, including a low coolant level, water pump failure, a bad radiator or damaged coolant hoses, a faulty thermostat, a poor head gasket, a loose drive belt, and a faulty radiator fan. Regardless of the cause of the problem, it must be addressed as soon as possible to prevent severe damage to the engine and cooling system components. Some of your parts may need a replacement.
What should I do if the temperature gauge provides low readings?
If your temperature gauge reads cold, most likely this will not cause any damage to the engine. Obviously, if you start a cold engine, it will need some time to warm up to reach its operating temperatures, especially in winter. However, this should take a short time after you start the engine. If your gauge continues to provide low readings, this is a symptom of a faulty engine cooling system component. In most cases, this can be caused by either a bad thermostat that is stuck in the open position or a bad temperature gauge or sensor. Of course, cold coolant will not lead to engine damage, but it can reduce your engine performance and increase emissions.
Temperature gauge troubleshooting and replacement
Most temperature gauges are maintenance-free parts designed to survive the test of time. In most cases high or low gauge readings are a sign of engine problems or cooling system problems, but not of the gauge itself. However, it can also fail to operate due to a manufacturing defect or damage.
A faulty or malfunctioning gauge can either move erratically or not operate at all. If a problem is caused by a failure of a related component, it may provide high or low readings. Here is the list of the most common gauge-related problems:
- Malfunctioning engine control unit or thermostat
- Bad wiring and connectors
- Faulty temperature sensor or switch
- Loose radiator cap
In many cases a bad temperature sensor can lead to reduced engine performance, increased emissions, starting problems, poor fuel economy and black smoke from the exhaust pipe. Any of these problems will cause the check engine light to turn on.