How to Replace a Cylinder Head Coolant Temperature Sensor

The coolant temperature sensor in your vehicle’s cylinder head plays a key role in the engine’s operation. It sends a signal to the electronic control unit (ECU) that provides information on the coolant temperature and supplies a signal to the temperature gauge in the dashboard.

Coolant temperature sensor failures are usually accompanied by engine running issues such as sluggish acceleration, hard starting when hot or cold, and the Check Engine or Service Engine Soon Light coming on in possible overheating conditions. If the Check Engine Light is on, diagnosis is usually straightforward by connecting a scan tool to the onboard diagnostic port and reading the fault code.

Part 1 of 1: Replacing the temperature sensor

Materials Needed

Step 1: Be sure the engine is cool. Locate the main pressure cap for the cooling system and open it enough to relieve any pressure in the cooling system, then reinstall the cap so it seals properly.

Step 2. Locate the coolant temperature sensor. Many engines have multiple sensors that look similar to each other, so an investment in either a paper version or an online subscription for your vehicle’s repair manual will pay dividends in a generally faster repair and reduce guesswork by guiding you to the exact part and location.

ALLDATA is a good online source that has most manufacturer’s repair manuals.

See the connector images below. The tab to lift to release the connector is at the top, toward the back of the connector on the left, the nub that it engages is at the top front of the one on the right.

cylinder head temperature sensor, both ends of connector

Step 3. Disconnect the electrical connector. The connector may plug into the sensor itself, or there may be “pigtail” wires leading from the sensor with the connector on the end of the wires. These connectors have a locking tab so that the connection remains secure. Using the pocket screwdriver (if needed), pry up the tab enough to clear the locking nub on the mating side, then separate the connection.

  • Tip: If you’re working on an older vehicle, be aware that the plastic on the connector may have become brittle from heat and the tab may break off, so use just enough pressure to raise the tab enough to release the connector.

removing the coolant temp sensor

Step 4. Unscrew the temperature sensor with an appropriately sized wrench or socket. Be aware that there may be coolant loss from the opening of the cylinder head when the sensor is removed, so be ready to screw in the new sensor to try to keep this at a minimum.

If equipped, use a new seal, usually a copper or aluminum washer, with the new sensor.

Step 5. Snug down the new sensor. Use the wrench and tighten just enough to ensure a good seal to the cylinder head.

  • Warning: Do not use excessive force when tightening the sensor! Too much pressure can result in a broken sensor which can be difficult to remove, or the threads in the cylinder head being stripped, which may require a new cylinder head, a very expensive repair.

Step 6. Reconnect the wiring. Make sure the wires are clear and will remain clear of any moving parts like the engine drive belt or pulleys, or any high heat items like an exhaust manifold.

Step 7. Verify that the engine coolant is at the correct level. Clear any OBD fault codes with the scan tool that haven’t corrected themselves now that there’s a proper signal from the temperature sensor.

Get a quote for a service: If you’re not quite comfortable diagnosing and changing your own coolant temperature sensor, a professional mechanic, such as from YourMechanic, will be happy to do it for you at your home or office.


Next Step

Schedule Coolant Temperature Switch (Sensor) Replacement

The most popular service booked by readers of this article is Coolant Temperature Switch (Sensor) Replacement. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Coolant Temperature Switch (Sensor) Replacement reviews

Excellent Rating

(298)

Rating Summary
275
9
0
4
10
275
9
0
4
10

Collins

12 years of experience
469 reviews
Collins
12 years of experience
GMC Acadia V6-3.6L - Coolant Temperature Switch (Sensor) - Atlanta, Georgia
Collins was very professional, knowledgeable, and on time. He has a great personality and helped me understand what was going on with my car. I highly recommend Collins.
Buick LeSabre - Coolant Temperature Switch (Sensor) - Atlanta, Georgia
Collins was very knowledgeable about the service and patient with my questions He also found other problems and explained so that I could understand. I will use him for these fixes too. Clean, professional personality. He was also on-time showing up a little early which was good for my anxiety when its starts getting close to appointment time. Today is only day one after my service and I took one small trip later on late afternoon and it was a good trip.

Marco

29 years of experience
215 reviews
Marco
29 years of experience
Subaru Outback H4-2.5L - Coolant Temperature Switch (Sensor) - Perris, California
Excellent mechanic!!! Marco provided a expert professional service on my vehicle today; thank you kindly.
Land Rover Range Rover Sport - Coolant Temperature Switch (Sensor) - Upland, California
Marco came to my house trice - he called 30 minutes before - he was very knowledge and pleasant - and he fixed the problem very fast. His service was outstanding - the best mecanic I have ever had - I am very pleased and I will GREATLT recommend his services

Diana

18 years of experience
88 reviews
Diana
18 years of experience
Volkswagen Tiguan L4-2.0L Turbo - Coolant Temperature Switch (Sensor) - Summit, New Jersey
Diana was very thorough and explained what she did, what she found and provided helpful insights. Came across as very knowledgable and trustworthy.

Chris

6 years of experience
78 reviews
Chris
6 years of experience
Lexus RX330 V6-3.3L - Coolant Temperature Switch (Sensor) - Jonesboro, Georgia
Awesome person awesome crew. Fast and efficient. Great customer service skills with the whole crew. Thanks for your help and I'll be using you guys again real soon

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Remove Cylinder Head Bolts
Removing Removing the head is a major step in removing the cylinder head (https://www.yourmechanic.com/article/how-to-buy-a-good-quality-cylinder-head). These head bolts hold the cylinder head to the engine block. The head bolts are long bolts that go through the cylinder head and head gasket...
How to Replace a Transmission Position Sensor (Switch)
Transmission position sensors (TPS) switch ensures a car is in Neutral or Park when started and shuts the car down if it's not in the right gear.
What is Engine Coolant or Antifreeze?
A A combustion engine works by burning a mixture of fuel and oxygen at temperatures over 200 degrees. Complete this process more than 2,000 times per minute, and you’ll understand how an engine can develop a lot of heat, and...

Related questions

Car still overheating, and hissing, even after changing the coolant.

Hi there. Some coolant leaks can be hard to find and may only appear when the system is under pressure. If you are getting a hissing noise it is possible that you have a leaking hose, but most of the...

Car slightly jerks, stalls, and then restarts

Hello. A faulty coil pack is likely the cause of the issue you are having. A less likely cause could be a clogged fuel filter (https://www.yourmechanic.com/services/fuel-filter-replacement) or fouled spark plugs (https://www.yourmechanic.com/services/spark-plugs-replacement). I suggest that you have a technician inspect your...

I was wondering if you could tell me what happens when the camshaft gears get stuck?

Hi and thanks for contacting YourMechanic. Lock camshaft gears will not turn the camshaft and cause the timing belt or chain to break. This is not your issue. What could be happening is the Throttle Position Sensor (https://www.yourmechanic.com/services/throttle-position-sensor-replacement) (TPS) or...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com