Coolant Temperature Sensor : Working, Symptoms & Replacement Cost

Coolant temperature sensor, which monitors the temperature of the engine coolant and transmits coolant temperature information to the ECU. Due to this, when the engine temperature is higher than normal, the ECU turns on the radiator fan so that the engine temperature remains normal.

But sometimes this happens due to a failure of the coolant temperature sensor, like engine overheating, coolant boiling from the radiator, AC stopping suddenly, etc. That’s why you should know about coolant temperature sensors in detail.

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.

This prevents the engine from overheating and helps maintain a normal engine temperature even during long periods of operation. 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.

Symptoms Of A Bad Coolant Temperature Sensor

Some symptoms of a bad coolant temperature sensor can be as follows, which are very important to pay immediate attention to, so that your vehicle’s engine can be protected from overheating.

1.Engine Overheating

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.

Why Does The Coolant Temperature Sensor Go Bad?

There can be many reasons for coolant temperature sensor failure, which is very important to investigate. This should then consider repair or replacement.

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 A Failed Coolant Temperature Sensor?

To diagnose and fix a coolant temperature sensor problem, you must first investigate its cause. After that, this problem can be fixed.

• First of all, you should check the wiring. If the wiring is damaged, repair it or install new wiring.
• Increase the coolant level in the radiator, and check the thermostat valve.
• Check the water pump. Because the coolant temperature sensor can also fail due to a bad water pump.
• Clean the radiator. If the radiator is leaking, have it repaired or replaced.
• 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.

FAQ’s

Given below are some frequently asked questions related to coolant temperature sensors with authentic answers, which will help in making this article useful content and fulfilling the user’s search.