Chevy Coolant Temperature Sensor Issues: Symptoms and Fixes

Chevy coolant temperature sensor issues vary from bad mileage to a cooling fan problem. The Chevy sensor helps your car to perform optimally by measuring the temperature of the engine control module.

Chevy Coolant Temperature Sensor Issues

In this article, our automobile team explains the symptoms and fixes of faulty Chevy temperature indicators, so read on!

What Are the Symptoms of Chevy Coolant Temperature Sensor Issues?

The symptoms of Chevy coolant temperature sensor issues include dark smoke from the engine, an illuminated engine check light, and a heating engine. You could also have a decreased power output as well as radiator fan issues as other symptoms of the problem.

– Thermal Strain on the Engine

If your Chevy engine overheats, it can be a symptom of temperature problems. The radiator fan is directly behind the radiator grille, removing heat from the car engine. The fan is controlled by electricity and gets its signal from the onboard computer.

Thermal Strain on Car Engine

Once it begins to receive a false signal, it might not turn on, which causes the engine to overheat. While many vehicles utilize an auxiliary temperature indicator for the fan, the vast majority make use of the same sensor.

– Illuminated Check Engine Lights

In addition to the engine overheating, you may see that the indicators to check your engine are on. This is one of the most common Chevy coolant indicator symptoms. If your car’s computer senses a problem with the signal your sensor is sending, it may cause your check engine lights to come on.

Illuminated Check Engine Lights

However, it is advisable to take the car to a qualified mechanic to confirm whether the illuminated check engine lights have anything to do with the engine sensor indicator.

– Emission of Black Smoke

Dark smoke can be a symptom of Chevy coolant indicator problems. Your car’s coolant helps the Engine Control Unit decide the amount of fuel-air mixture available for combustion. A bad sensor leads to a rich fuel-air mixture. This means there’s too much fuel used, which may not burn off in the exhaust, leading to the black fumes that the exhaust pipe emits.

Black Smoke Car Emission

While a little bit of dark smoke might not render your car useless, it is an indicator of sensor problems and you should get it checked with a professional mechanic. In very severe cases, the smoke can become very dense and noticeable to everyone nearby.

– Rough Idling

This issue is another common symptom seen in sensor problems. Due to a faulty sensor, there is a change in the fuel-air mixture.

Signs of Rough Idling

This will cause the engine to vibrate at a low speed, leading to power losses and other erratic presentations. This is because the engine becomes more sensitive to the fuel-air ratio when it is idle.

– Inadequate Mileage

This is another symptom of temperature indicator problems. A faulty ECT sensor can send a poor signal to the computer, indicating that it is overheating when in actual fact, it is not.

Inadequate Car Mileage

This will inject more fuel into the engine and cause it to be heated more quickly. This can decrease fuel economy and, invariably, the vehicle’s performance in the long run.


Although it can be a vague symptom that suggests a myriad of problems, if it comes before the other listed problems, it’s an indicator of a faulty sensor.

– Spoiled Electrical Cooling Fans

Another suggestive symptom of a faulty ECT is the radiator fans not coming on. While many cars have two separate sensors for the dashboard, engine, and radiator fans, some cars have one that serves all the car’s components. If your Chevy falls into the latter category, the sensor can fail to accurately read the engine’s temperature, which might cause the radiator fans not to work.

Car Electrical Cooling Fans

The opposite of this can also happen, resulting in the engine heating beyond its normal temperature and causing it to get damaged.

– Rough Hard Start

Although it isn’t as common as most other symptoms, a poor start condition is usually a presentation of a broken sensor. This is because the sensor continually provides a hot reading even when it is perpetually cold.

Rough Hard Start of Car


This will usually only happen when the vehicle’s engine is either hot or cold. As a result, this causes a lean fuel-air situation, which exponentially increases crank times and difficulty starting.

– Erratic Temperature Level

This is another symptom of a bad sensor problem. The input from the coolant indicator determines the engine temperature. Once the system fails to gather this information, it can cause an erratic temperature gauge as you drive.

Erratic Car Temperature Level

While this is a definite symptom of faulty sensor problems, you should have a mechanic take a look at your cooling system.

– Emission Dysregulation

Emission dysregulation issues can be a symptom of a faulty coolant indicator. The indicator plays a huge role in the performance of the engine as it monitors the temperature of the engine coolant and provides accurate information for proper fuel-air mixture and ignition timing.

Car Emission Dysregulation

Once broken, it can provide incorrect readings to the dashboard, leading to decreased engine performance. If the sensor indicates a lower temperature than the actual reading, the Engine Control Unit believes the car is still in a warm-up phase and provides a rich fuel mixture.

Conversely, the ECU provides a lean ratio if the sensor indicates a higher temperature. This emission dysregulation caused by the sensor can result in the vehicle failing to meet the required emission standards.

– Reduced Power Output

A decreased power output can be a symptom of a faulty ECT sensor. Suppose the sensor malfunctions and gives the engine control unit incorrect temperature readings. In that case, the ECU may not be able to regulate its fuel mixture and ignition timing properly.

Reduced Car Power Output Solved

This can result in a fuel mixture that is either too lean or too rich, leading to inefficient combustion and poor fuel economy. Inefficient combustion also leads to a decreased power output from the engine as it is not performing as it ought to.

– Faulty Water Pump

A bad engine indicator can also be due to a damaged water pump. If your water pump needs replacement before it has its life expectancy, it indicates that something might be wrong with your coolant sensor. This occurs when the faulty engine coolant indicator reads a higher temperature than usual.

Faulty Car Water Pump

When that happens, the ECU will try to take corrective measures to balance out the damage. The Engine Control Unit does this by increasing the fuel injection and the water pump speed so it pumps more water to cool out the engine.

What Causes Chevy Coolant Temperature Sensor Issues?

The common causes of Chevy coolant temperature sensor issues include sensor wear and issues with emission regulations. Aside from these, coolant indicator issues such as leakage may be traceable to contaminants in the coolant, damage to the sensor, and even corrosion.

– Emission Regulation Issues

While an issue with the emission regulation can cause Chevy coolant issues, it is not a direct cause. However, certain conditions that are linked to its noncompliance can contribute to the sensor’s fault. For instance, if a vehicle consistently operates under functions that lead to a low emission, such as running too lean, it can strain the engine and its components, including the coolant. This increased tension, as well as prolonged exposure to contaminants, can lead to the eventual malfunction of the sensor.

– Cooling Sensor Leakage

A leak in the cooling sensor can cause the engine sensor to be faulty due to the introduction of external contaminants. If the cooling system leaks, coolant may seep into places it isn’t meant to be in, including the sensor housing. This can lead to electrical short circuits or damage to the internal operations of the sensor’s components. It can also result in an inaccurate performance or complete failure of the sensor.

Additionally, if the leaks introduce debris or contaminants, it can hamper its functionality and precision. Therefore, a leak in the cooling sensor can affect the integrity of the sensor, leading to its malfunction.

How To Fix Chevy Coolant Temperature Sensor Problems?

To fix your Chevy coolant temperature sensor problems, you can use a diagnostic tool to confirm that the coolant temperature is indeed faulty. You can also replace the sensor or reconnect the electrical connector. To fix the issue, ensure your safety by first disconnecting the battery.

– Install a New Sensor

You can fix your Chevy temperature indicator issues by replacing the sensor. To do this, you can start by ensuring your safety and locating the sensor. Then, disconnect the battery to avoid electrical issues and carefully detach the electrical connector from the sensor.

Take note of the seals or gaskets that may need to be replaced. Also, take note of the coolant level. You can install the new sensor by inserting it in the mounting hole and securely attaching the electrical connector. This will make the sensor work.

However, get a professional if you’re not confident about performing the replacement yourself. You should also consult a certified mechanic for the temperature sensor replacement cost.

Take note that the average longevity of most coolant temperature sensors is about 100,000 miles. However, the longevity is different for different vehicles. It can fail much earlier if you do not properly maintain the engine coolant temperature sensor, so make sure that your vehicle components are always maintained well.


– What Is the Maximum Driving Distance With a Bad Coolant Temp Sensor?

There is no maximum driving distance with a bad coolant temperature sensor. You can drive far distances, but it is not recommended as many symptoms will become more problematic. For instance, an inoperable fan caused by a broken coolant engine can lead to overheating.

– What Will Happen if You Unplug the Chevy Coolant Temperature Sensor?

If you unplug the Chevy coolant temperature sensor, it can cause the idle speed to be higher. This is because the engine will think the car’s temperature is lower than it is. In addition, the fuel-air ratio can turn richer and black smoke may be emitted.

– Can a Faulty Chevy Coolant Temp Sensor Lead to Rough Idle?

Yes, a faulty Chevy coolant temperature sensor can lead to rough idle because it can send wrong signals to your Chevy’s ECU. As a result of these false signals, the Engine Control Unit adjusts the fuel injection into the combustion chamber, leading to a rough idle.

Could a Faulty Coolant Temperature Sensor Cause the Car Heater to Blow Cold Air While Idling?

A faulty coolant temperature sensor can indeed be the reason behind a car heater blowing cold air. When the sensor fails to provide accurate readings, it can send incorrect signals to the car’s heating system, causing it to malfunction. Consult a professional for a car heater blowing cold air fix.


You no longer need to panic about your Chevy coolant temperature issues symptoms.

Here are our final thoughts on the main points discussed in the article:

  • Some possible symptoms of Chevy coolant temperature problems are black fumes emitting from the engine, an illuminated engine check light, and an overheating engine.
  • You could also have decreased power output and radiator fan issues.
  • Chevy coolant temperature indicator symptoms can be fixed using a diagnostic tool to confirm that the coolant temperature is faulty, disconnecting the battery, or locating the sensor.
  • You can also replace the sensor or reconnect the electrical connector. Make sure you consult a professional mechanic for proper diagnosis before repairs.

With the information in this article, once you notice your Chevy sensor symptoms, you should be able to diagnose and fix the problem immediately.

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