- A coolant temperature sensor (CTS) or engine coolant temperature sensor (ECTS) measures the temperature of your engine’s liquid coolant or antifreeze.
- This is important because it will help your vehicle’s engine control unit (ECU) know how heated your engine is. This data is used by the ECU to calculate the amount of fuel to be injected in the engine.
- Most vehicles are installed with primary ECT sensors while some have cylindrical head temperature sensors or CHT. The type of sensor installed in your vehicle will depend on your vehicle’s year, make, and model.
- Symptoms of a faulty CTS include increased fuel consumption, black smoke from exhaust pipes, check engine light, and engine overheating.
- A typical CTS replacement costs around $50 to $250. To ensure that you are getting the right fit, enter the correct vehicle details into our search engine.
Your engine’s cooling system is important to keep your vehicle’s internal combustion engine at an optimal temperature. A frequently overheated engine may damage engine components in the long run and decrease your vehicle’s performance.
The cooling system works with the help of a substance called a coolant. In a nutshell, this substance absorbs the heat that is generated by a running engine. Did you know that there are sensors installed in your engine to detect the temperature of your vehicle’s coolant? In this article, you will get to know more about coolant temperature sensors, how they function, and when you should have one replaced.
What does a coolant temperature sensor do?
From the name of the car part itself, you may already have an idea of what it is for. To put it simply, your coolant temperature sensor (CTS) or engine coolant temperature sensor (ECTS) is responsible for measuring the temperature of your engine’s liquid coolant or antifreeze.
Coolant temperature monitoring is important because it will help your vehicle’s engine control unit (ECU) know how heated your engine is. From this data, the ECU can determine and readjust the vehicle’s fuel injection accordingly. The temperature of your engine determines how much fuel is needed by your engine. As your vehicle’s engine warms, it will need less fuel to run.
How does your vehicle’s CTS measure your coolant’s temperature? The tip of your CTS usually protrudes into one of the coolant passages. However, the exact location of your sensors will depend on what type of CTS your vehicle uses.
Your vehicle’s CTS works similarly to a thermistor, which also uses the principle of electric resistance. A typical CTS is a kind of Negative Temperature Coefficient (NTC) thermistor. This means that its electrical resistance decreases as the temperature increases. To get an accurate reading, the ECU sends out regular voltage to your sensors. Because the resistance of the sensor decreases with temperature, the ECU can now monitor and calculate the coolant temperature.
What are the types of coolant temperature sensors?
Most vehicles are installed with more than one coolant temperature sensor. Most of them are equipped with a primary ECT sensor or ECT sensor 1. Some cars, however, use cylinder head temperature sensors or what is commonly called CHT sensors. Again, this information will greatly be dependent on your vehicle’s year, make, and model.
Primary ECT Sensor
In most vehicles, a primary ECT sensor is installed near the thermostat, specifically on the thermostat housing or on the cylinder head. Usually, a second temperature sensor is installed on another part of your engine such as the radiator.
Cylinder Head Temperature Sensors or CHT sensors
Some vehicles have this kind of sensor installed instead of the usual ECT sensor. Some also have these installed in addition to a primary ECT. The difference between these two sensors is that CHT sensors are not immersed in coolant. Instead, it measures the temperature in the cylinder metal. Even when your vehicle is losing coolant, your CHT sensor can still accurately measure the temperature of your engine, preventing your vehicle from overheating.
OEM vs OE Coolant Temperature Sensors
When looking for a coolant temperature sensor replacement, you may also encounter the term OEM and OE replacements. Which is better?
OEM stands for Original Equipment Manufacturer. This means that OEM coolant temperature sensors are made by your vehicle’s authorized manufacturer. OEM car parts are usually priced higher than OE. If you have the budget for it, it is good to invest in OEM car parts. Since they come from your vehicle’s authorized manufacturer, you can be assured of the quality of your CTS.
OE replacements are made by third-party manufacturers and other car part manufacturing companies. Although they are priced lower than OEM, most OE car parts perform just like OEM. If you’re planning to buy an OE CTS, make sure to get it from legitimate car retail shops. In CarParts.com, you can find high-quality OE coolant temperature sensors at an equally reasonable price.
OE replacements are just as good as OEM. At the end of the day, it all boils down to preference. What is important is ensuring the quality and compatibility of your coolant temperature sensors before buying a replacement for your vehicle. You may also consult your trusted mechanic for information regarding the type of sensors you should buy.
What are the symptoms of a bad coolant temperature sensor?
Just like any other engine sensor, your coolant temperature sensor may malfunction or get damaged over time. Here are the common symptoms that may indicate that your coolant temperature sensor is nearing the end of its life:
Increased Fuel Consumption
Since your vehicle’s PCM or ECU uses the coolant temperature sensor data to evaluate the amount of fuel to be injected in your engine, a bad coolant temperature sensor may send wrong signals to the PCM, leading to fuel miscalculation. This may cause your vehicle’s fuel economy to drop significantly. In the long run, this symptom may lead to poor engine performance.
If you notice a significant increase in your vehicle’s fuel consumption, your coolant temperature sensors may be to blame. However, take note that there are other reasons why your vehicle may experience a drop in fuel economy. Problems such as incorrect tire pressure, faulty 02 sensors, and other faulty components in your internal combustion engine are only a few of those reasons.
To know what specifically caused the problem, it is best to have your vehicle checked by your trusted mechanic.
Similar to increased fuel consumption, this may be caused by wrong signals coming from your vehicle’s CTS. The PCM may miscalculate signals from your faulty CTS, leading to wrong adjustments and causing your vehicle to eventually overheat.
Black smoke from exhaust pipes
Faulty CTS readings may cause incorrect air-fuel mixture in the engine. If the fuel in the engine is excessively rich, it may not be burned properly in the combustion chamber. This may cause fuel to get burned up in your exhaust pipes, causing black smoke.
It is important to note that this symptom is not exclusive to a faulty coolant temperature sensor. This may be caused by other bad components in your engine.
Check Engine Light
Lastly, a bad coolant temperature sensor will cause your “check engine light” to turn on. Once your “check engine light” turns on, regardless of what the reason is, it is advisable to have your vehicle checked by your trusted mechanic.
How much does a coolant temperature sensor cost?
A typical coolant temperature sensor replacement usually costs around $50 to $250. It can be sold individually, in sets of two, or as a part of a kit. Many brands offering high-quality OE coolant temperature sensors. Make sure to consult your vehicle manual or talk to your trusted mechanic regarding the specifics of your vehicle’s coolant temperature sensors.
Finding the right fit
CarParts.com offers many high-quality coolant temperature sensors for you to choose from. To ensure that you are getting the right fit, enter your vehicle’s specific year, make, and model into our search engine. Browse our wide selection of coolant temperature sensors and choose the one that is compatible with your vehicle.
There are many self-help videos online on how to replace a coolant temperature sensor. However, it is best to leave the job to a trusted professional. A wrongly installed coolant temperature sensor may cause more damage to your vehicle’s engine.
How to Choose the perfect Coolant Temperature Sensor
Heat is as much a normal fixture in an engine as a television set is to a couch potato. It's all good though as long as the heat is manageable. What isn't good is when the temperature rises beyond the prescribed level. Everybody knows what could happen then-an engine breakdown may be on the horizon. Fortunately, a cooling system is in place in order to prevent such a scenario from happening. The coolant temperature sensor is one of the centerpieces of this system.
The "Master" Sensor
The coolant temperature sensor, which is commonly located near the thermostat, helps in keeping engine heat at an appropriate level. As its name implies, the coolant temperature sensor measures just how hot or cold the engine is. The cooling system uses that information to effectively deal with the engine temperature. Is the engine too hot? If it is, the sensor will cause the cooling fan to be turned on. The coolant temperature sensor is definitely an intuitive component. It's basically the "brain" of the cooling system, which is why it's referred to as the "master" sensor.
The coolant temperature sensor isn't called the "master" sensor just because it tells the cooling fan when to turn itself on or off. No, the coolant temperature sensor is better than that. How so, you ask? Well, it's also used in determining whether the engine needs a richer or a leaner air-fuel mixture and when to open or close emission channels. Basically, the sensor does a lot for your automobile, thus its nickname is well-deserved.
Even the "Master" Can be Broken
Pretty much all automotive components give out at some point. The "master" sensor isn't exempted from that. Don't worry, you'll know when the coolant temperature sensor is about to go busted via these warning signs:
- Decreased fuel economy due to richer air-fuel mixtures
- Increased emissions (this is related to the symptom above)
- Engine shutdown (because of the bad sensor's inability to send accurate engine temperature information)
Getting a Replacement
Obviously, you'd need to get a replacement for your faulty coolant temperature sensor. An OEM coolant temperature sensor should prove to be a great choice-it's reliable, durable, and will fit in your vehicle nicely. Another good thing about it is that it's very affordable. In fact, you can get a brand-new OEM coolant temperature sensor for as low as $5! There are variants though that can cost as much as $30, but they're still inexpensive by any means. Installing an OEM coolant temperature sensor shouldn't prove to be much of a challenge too, especially if you're an experience DIYer.
How to Install a New Cooling Temperature Sensor
The coolant temperature sensor is considered as the "brain" of the engine cooling system. If it's not in good condition, it's safe to say that your engine will be plagued by overheating problems. A broken sensor isn't hard to replace, and we'll guide you every step of the way on how to do it.
- Catch pan
- Wrench (the size needed depends on your vehicle's make and model)
- Teflon tape
- 1 gallon of coolant
Step 1: Before anything else, let the engine cool down so that you won't hurt yourself.
Step 2: The next step is to drain the radiator. Once the engine is cool, place a catch pan underneath the radiator and drain roughly 1 gallon of coolant. Afterwards, disconnect all the electrical connections on the coolant temperature sensor.
Step 3: Detach the wire that runs from the coolant temperature sensor to the engine block. You can now remove the sensor by using a wrench.
Step 4: Wrap the threads of your new coolant temperature sensor with Teflon tape. After that, you can finally install your brand-new coolant temperature sensor. Make sure that you don't over-tighten it as doing so will significantly affect the sensor's function.
Step 5: Once your new coolant temperature sensor is in place, you'd have to replace the coolant that you drained earlier. Start by taking off the radiator cap and turning on the engine. Wait until it warms up. When your engine reaches 195 degrees ?F, your thermostat will start working. The remaining coolant in the system will begin flowing as well. At this point, you may refill the radiator with coolant. Close the cap afterwards.
Step 6: Test if your newly installed coolant temperature sensor is working properly by letting the engine reach 215 degrees ?F. Once it reaches that temperature, the fans should activate themselves. If they did, congratulate yourself on a job well done. If not, then you may have over-tightened your placement of the sensor, your new sensor may be defective, or your fans may be faulty.