The coolant temperature sensor is a vital component in the engine, sending an engine temperature signal to the vehicle’s ECU.
The function of all sensors used in modern vehicles is to send data signals about the working condition of vehicle parts to the vehicle’s engine control module. Similarly, the vehicle’s engine coolant temperature sensor, which monitors the temperature of the engine coolant,
Through this post, we will learn in detail about the engine coolant temperature sensor. Like, what is a coolant temperature sensor? Engine Coolant Temperature Sensor Failure Causes, Symptoms, and How Much Does a Replacement Cost?
What Is Coolant Temperature Sensor?
The engine coolant temperature sensor is a vital component of the coolant system of modern vehicles, monitoring the temperature of the coolant fluid flowing through the vehicle’s engine and transmitting this information to the ECU.
Due to this, the engine avoids overheating and helps maintain a normal engine temperature even during long running times.
The engine coolant temperature sensor is used in vehicles in which the radiator fan is operated by the ECM. The engine coolant temperature sensor is often located in any part of the engine’s coolant system.
How Does Coolant Temperature Sensor Work?
The function of the engine coolant temperature sensor in modern vehicles is to transmit a coolant fluid temperature signal to the vehicle’s ECM when the engine is running.
The engine coolant temperature sensor signals the vehicle’s ECM about the increasing temperature of the vehicle’s engine coolant, and the vehicle’s ECM turns on the radiator fan when the temperature reaches a certain point based on the signal from the coolant temperature sensor.
This reduces the temperature of the coolant liquid in the engine, due to which the engine temperature remains normal. Due to which the engine is saved from overheating. The engine coolant temperature sensor is used in vehicles with an electronic radiator fan.
In older-technology vehicles, the radiator fan is continuously rotated by a serpentine belt when the engine is running. The coolant temperature sensor is used to maintain a normal engine temperature.
Symptoms Of A Bad Coolant Temperature Sensor
If your vehicle’s coolant temperature sensor is bad, common symptoms include inaccurate temperature readings on the dashboard, AC shutting off suddenly, engine overheating or running too cold, poor fuel efficiency, steam under the hood, rough idle, and increased emissions.
Let’s take a closer look at the symptoms of a bad coolant temperature sensor so you don’t get confused with other engine overheating problems.
A bad engine coolant temperature sensor can be a major cause of engine overheating while running. A bad engine coolant temperature sensor is unable to send a signal of the engine coolant’s liquid temperature to the vehicle’s ECM.
This causes the vehicle’s ECM to be unable to operate the radiator fan when the engine is overheated, due to which the engine starts overheating.
2.Temperature Gauge Showing High Temperature
Whenever the Engine Coolant Temperature Sensor is defective or unable to function. Then the engine temperature starts to exceed normal.
Due to this, the temperature gauge in the cluster meter of the vehicle starts moving from a normal temperature to a high temperature, and in no time the temperature gauge comes to the red line. A red light on the temperature gauge indicates overheating.
3. Unusual Engine Noise
The engine starts to overheat due to a bad engine coolant temperature sensor, which causes a change in the sound of the engine’s running condition.
The engine starts making knocking noises because the piston of the engine starts sticking to the sleeve due to excessive heating.
4. Engine Vibration & Jerks
A bad engine coolant temperature sensor can sometimes cause engine vibrations and jerks. A bad engine coolant temperature sensor is unable to signal the engine temperature to the vehicle’s ECM.
Due to this, the ECM of the vehicle is not able to set the correct ratio of air and fuel in the fuel mixture of the engine. which causes the fuel combustion process in the internal combustion chamber of the engine to get disrupted. Due to this, the engine starts having problems with vibration and jerking.
5. Engine Misfire
If the engine coolant temperature sensor is damaged while running. So this sensor is unable to report the engine temperature to the ECM of the vehicle.
This can cause the ECM to impair fuel combustion in the engine’s internal combustion chamber, or the firing order of the fuel mixture is not timing with the position of the pistons. Due to this, the problem of misfiring can also be seen in the engine.
6. Check Engine Light
In modern cars and other vehicles, the main symptom of any sensor malfunction or any other type of problem is the illumination of the check engine warning light in the cluster meter of the vehicle.
Which indicates a fault related to one or more sensors in the vehicle. If this happens, diagnose the problem by scanning the vehicle’s system with an OBD scanner.
7. Reduced Engine Power
A bad engine coolant temperature sensor can cause a number of engine malfunctions. A bad Engine Coolant Temperature Sensor can cause the vehicle’s ECM to mess up the correct ratio of air and fuel in the fuel mixture, which directly affects the power and performance of the engine and a failing engine coolant temperature sensor could result in reduced engine power and performance.
Causes Of Bad Coolant Temperature Sensor
- Physical Damage
- Low Coolant Level in Radiator
- Wiring Issue
1. Physical Damage
The engine coolant temperature sensor, contamination, and weather effects can cause a malfunction of the engine coolant temperature sensor or any sensor in the vehicle, or else the sensor may get damaged or broken due to something colliding with it, and as the engine coolant temperature sensor ages over time, it can cause a complete failure of its functioning.
2. Low Coolant Level in Radiator
In vehicles, the coolant temperature sensor is in contact with the coolant that flows from the radiator to the engine. Thereby, the coolant temperature sensor transmits the engine coolant temperature signal to the vehicle’s ECM.
But when the coolant level in the radiator is low, the Engine Coolant Temperature Sensor is unable to send coolant temperature data to the ECM. Therefore, a low level of coolant in the radiator can also be the main reason for its failure.
3. Wiring Issue
The wiring to the engine coolant temperature sensor is connected to the ECM, through which any electronic sensor of the vehicle provides information to the ECM.
But many times the wiring of the sensor gets damaged or cut somewhere. This causes the engine coolant temperature sensor to fail to send an engine temperature signal to the vehicle’s ECM.
How To Fix It?
To diagnose and fix a coolant temperature sensor problem, you must first investigate its cause. After that, this problem can be fixed.
- If you observe these symptoms in your vehicle, then the first thing you will need to do is scan the vehicle’s system with an OBD digital scanner.
- After this, you will know the problem related to it in the scanner.
- You should check the wiring. If the wiring is damaged, repair it or replace it with a new one.
- Top up the coolant level in the radiator.
- Check the thermostat valve.
- Check the water pump. A bad water pump can also cause the coolant temperature sensor to malfunction.
- Clean the radiator. Repair or replace if leaking.
- Test the coolant temperature sensor. If the sensor is bad, replace it with a new one.
- A blown engine head gasket can also disrupt the functioning of the coolant temperature sensor.
Coolant Temperature Sensor Replacement Cost
Coolant temperature sensor replacement cost depends on the vehicle model and the mechanic’s location.
On average, the replacement cost of a coolant temperature sensor in typical vehicles can range between $300 and $450, including mechanic’s labor costs.
A coolant temperature sensor can cost $200 to $300, and the labor cost for a mechanic to replace it can be between $100 and $150. These estimated costs may be higher or lower depending on the location of the parts and mechanics.
Q. What happens when the coolant temperature sensor goes out?
A bad or failing coolant temperature sensor may be sending an incorrect coolant temperature signal to your vehicle’s ECM, or the sensor does not send a signal at all. This may cause the vehicle’s ECM to be unable to operate the engine’s coolant system. which can cause overheating of the engine.
Q. Can a coolant temperature sensor cause overheating?
Yes, a bad or failing coolant temperature sensor can cause engine overheating. Because in modern vehicles, this sensor gives the wrong information about the temperature of the engine to the ECM of the vehicle.
Banty is the owner of Autorepairszone.com & is also a vehicle mechanic by profession. We have almost 12 years of experience in the field of automotive repair, and we strive to provide you with accurate information about vehicle malfunctions and repairs based on our experience.