
Water temperature during the production process is an important parameter to monitor. Water temperature sensors are key components in modern industries, automobiles, home appliances, and other fields. Their core function is to accurately sense and feedback temperature information.
Sino-inst offers a variety of sensors for measuring water temperature. The electrical signal transmitted from the sensor to the data logger can be converted into various units of measurement. These include °C, °F, and °K.
About Water Temperature Sensors
A water temperature sensor is a type of temperature sensor. It can measure the temperature of water. It is a core component for monitoring the temperature of an engine cooling system. It can be widely used in meteorology, agriculture, aquaculture, laboratories, and other fields.
Water temperature sensors can measure coolant temperature in real time. They ensure that the engine operates within the normal temperature range. They can convert temperature changes into voltage signals (such as 0-5V). When the water temperature is abnormal, they trigger a warning light or stop the engine to prevent damage from overheating.
How do Water Temperature Sensors Work?
Temperature sensors are primarily categorized into contact and non-contact types. Common types include thermocouples, RTDs, thermistors, and infrared temperature sensors. Sino-inst primarily offers thermocouples and RTDs.
Thermocouples and thermistors are both contact-type temperature sensors. They are in direct contact with the object being measured. And they measure temperature through heat conduction.
Thermocouples are made by joining two dissimilar metals. They use temperature differences to generate an electromotive force. They are used in high-temperature environments and have a fast response speed. However, their accuracy is relatively low.
The working principle of a thermocouple is based on the thermoelectric effect. Two different conductor materials generate an electromotive force when there is a temperature difference between them. This enables temperature measurement.
The magnitude of the generated thermoelectric force is a function of the temperature difference between the two ends. The formula is:
EAB(T, T0)=EAB(T)−EAB(T0). Where T is the hot end temperature and T0 is the cold end temperature.
RTDs measure temperature by exploiting the property of metal resistance that changes with temperature. The core principle is that the resistivity of a material is related to temperature by a specific function. It has high accuracy and stability. It is suitable for applications that require high precision.

Common Water Temperature Sensors
The following are temperature sensors that our company can use to measure water temperature:
The Role of Water Temperature Sensors in Industry
The water temperature sensor monitors the coolant temperature in real time. It converts the temperature signal into an electrical signal and transmits it to the ECU. This serves as the core basis for adjusting parameters.
The water temperature sensor also participates in dynamic parameter adjustment. It increases the fuel injection amount at low temperatures. And it reduces the fuel injection amount at high temperatures. This optimizes combustion efficiency.
Applications of Water Temperature Sensors
Where Should a Water Temperature Sensor be Installed?

- At the rear end of the cylinder head or in the cylinder block water channel.
Most models install it near the rear end of the cylinder head or in the cylinder block water channel, near the thermostat. - At the coolant outlet or manifold.
Some models choose to install it at the outlet or manifold for quick response to temperature changes. - Below the intake manifold or near the water pump.
A few models install it here.
Installation Precautions
- Avoid contamination of the sensor during installation. Ensure adequate contact with the coolant.
- Failure to connect the wires in the correct sequence may damage this device and any instruments connected to it.
- Exceeding the maximum input voltage of this device will cause damage to the device.
- Please read this manual thoroughly before use.
How do I know if my water temperature sensor is damaged?
- Abnormal Dashboard Water Temperature Gauge
- If the needle is stationary, fluctuates, or explodes, it could be due to an internal sensor circuit breakage, unstable resistance, or a short circuit.
- Difficulty in cold starting
- If the sensor misreports a low temperature signal, the ECU will inject fuel as if the engine were warm. We need to ignite the engine multiple times to start it.
- Unstable idle speed
- Abnormal fuel mixture concentration can cause the engine speed to fluctuate. This is commonly caused by distorted sensor signals.
- Significant increase in fuel consumption
- If fuel injection increases abnormally by 15%-30%, fuel consumption may surge by 22%. This indicates an issue with the coolant temperature sensor.
- Engine Overheating/Overcooling
- Continuous fan operation or abnormal coolant circulation can cause water temperature fluctuations.
Troubleshooting Water Temperature Sensors
The water temperature sensor can be repaired using the following methods:
1. Basic Testing Method
We can use a multimeter to measure the supply voltage (approximately 5V) and resistance value (approximately 2.5kΩ at 20°C and approximately 0.3kΩ at 80°C). Then, we compare the water temperature data from the OBD diagnostic tool with the instrument display value (the error should be <5°C).
2. Wiring Troubleshooting
We should check the plug for oxidation, damaged wiring, or poor contact.
3. Environmental Verification
Use an infrared thermometer to measure the sensor surface temperature (normally ±5°C). If the temperature exceeds the specified range, replace the sensor.
4. Dual-Sensor Vehicle Handling
If the data from the primary and secondary sensors do not match, prioritize repairing the dedicated meter sensor.

More Temperature Measurement Solutions
Water temperature sensors are essential components in modern industry. They provide crucial data support for stable equipment operation, optimized energy efficiency, and safety protection.
Sino-Inst offers a wide variety of industrial temperature sensors and transmitters. These include RTDs, thermocouples, and PT100s, and they are also available with 4-20mA outputs. These sensors can measure not only water temperature but also the temperatures of a variety of media.
If you need to purchase flow and temperature sensors or have any technical questions, please feel free to contact our sales engineers!