PRO Courses Hot Guides Tech Help Pro Expert Videos About wikiHow Pro Upgrade
QUIZZES All Quizzes Hot Love Quizzes Personality Quizzes Trivia Quizzes Taylor Swift Quizzes
EDIT Edit this Article
EXPLORE Tech Help ProAbout UsRandom ArticleQuizzes Request a New ArticleCommunity DashboardTrendingForums Arts and EntertainmentArtworkBooksMoviesComputers and ElectronicsComputersPhone SkillsTechnology HacksHealthMen's HealthMental HealthWomen's HealthRelationshipsDatingLoveRelationship Issues Hobbies and CraftsCraftsDrawingGamesEducation & CommunicationCommunication SkillsPersonal DevelopmentStudyingPersonal Care and StyleFashionHair CarePersonal Hygiene Quizzes Love Quizzes Personality Quizzes Fun Games Arts and EntertainmentFinance and BusinessHome and GardenRelationship Quizzes Cars & Other VehiclesFood and EntertainingPersonal Care and StyleSports and Fitness Computers and ElectronicsHealthPets and AnimalsTravel Education & CommunicationHobbies and CraftsPhilosophy and ReligionWork World Family LifeHolidays and TraditionsRelationshipsYouth
LOG IN
Log in
Social login does not work in incognito and private browsers. Please log in with your username or email to continue. FacebookGooglewikiHow Account No account yet? Create an account
RANDOM
Home
Random
Browse Articles
TrendingNew
Quizzes & Games
All QuizzesHot
Love Quizzes
Personality Quizzes
Fun Games
Dating Simulator
Learn Something New
Forums
Courses
Happiness Hub
Explore More
Support wikiHow
About wikiHow
Log in / Sign up
Terms of Use wikiHow is where trusted research and expert knowledge come together. Learn why people trust wikiHow
Categories
Cars & Other Vehicles
Cars
Car Maintenance and Repair
How to Replace a Thermostat in a Car Download Article Co-authored by Hunter Rising Reviewed by Jason Shackelford
Last Updated: January 21, 2026 Fact Checked
Download Article
Removing the Old Thermostat
|
Installing the New Thermostat
|
Refilling the Coolant
|
Video
|
Tips
|
Warnings
|
Things You'll Need
|Show more|Show less X
This article was reviewed by Jason Shackelford and by wikiHow staff writer, Hunter Rising. Jason Shackelford is the Owner of Stingray Auto Repair, a family owned and operated auto repair shop with locations in Seattle and Redmond, Washington. He has over 24 years of experience in auto repair and services, and every single technician on Jason’s team has more than 10 years of experience. There are 13 references cited in this article, which can be found at the bottom of the page. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 124,023 times.
A vehicle’s thermostat controls the amount of coolant running through the engine so it doesn’t overheat. But if your temperature gauge consistently stays past the ¾-mark or in the red zone when you run your vehicle, it could be a symptom of a bad thermostat that needs to be replaced. Luckily, it only takes a few minutes and a couple of tools to change your thermostat yourself. Our guide will show you how to remove the bad thermostat and replace it with a new one!
Steps
Part 1 Part 1 of 3:
Removing the Old Thermostat
Download Article
1 Wait for the engine to cool down if you drove recently. As you drive your vehicle, the coolant running through the engine heats up and could cause severe burns. Before you make your repairs, give your vehicle 30–60 minutes so it can cool off. To check the temperature, open the hood and lightly touch your engine to see if it feels hot. If it’s cool to the touch, then you can work safely.
Never work on your vehicle while it’s running since you could get injured.
Try leaving the hood open to help your engine cool off faster.
2 Take the cap off of your radiator. Locate your radiator, which is a long black box under your hood and in the front of your engine bay directly behind the grille. Look for a circular cap on top of the radiator and turn it counterclockwise to loosen it. Set the cap aside while you’re working so you don’t misplace it.[1]XResearch source
Never open the radiator cap if your engine is still hot. The radiator may have built-up pressure, which could spray hot coolant when you open the cap.
If you notice coolant leaking out from the radiator cap before you unscrew it, buy a replacement.
Variation: Your vehicle may have a clear plastic reservoir near the back corner of the engine bay that stores additional coolant. You can unscrew the reservoir cap instead of the radiator cap.
Advertisement
3 Put a drip pan underneath your radiator’s drain plug. Look underneath your vehicle at the bottom of the radiator and look for a small plastic wingnut or plug. Slide a drip pan directly under the plug so your coolant doesn’t spill everywhere or make a mess while you’re working.[2]XResearch source
You can buy a drip pan from an automotive supply store. If you don’t have a drip pan, you can also use a bucket.
You may need to jack your vehicle onto stands if you can’t get under your vehicle to find the drain plug.
4 Drain half of the coolant out from your radiator’s drain valve. Turn the drain plug on your radiator counterclockwise until you see a steady stream of coolant pour into the drip pan. Check the levels of the coolant by looking into the radiator. You only need to remove enough coolant to expose the thermostat, so once half of the coolant flows out from the plug, turn it clockwise to tighten it again.[3]XResearch source
You do not need to drain all of the coolant from your vehicle.
Save the coolant you drained since you can keep using it.
If your coolant is filled with dirt or floating debris, you may need to flush your radiator to clean it.
5 Unbolt the thermostat housing from the engine block with a ratchet. Follow the hose from the top of your vehicle’s radiator to the side of your engine. Where the hose connects to the engine will be the housing for the thermostat. Find the 2 bolts on each side of the housing’s flange and turn them counterclockwise with a ratchet. Once you loosen the bolts, you can easily lift the housing up to detach it from the engine.[4]XResearch source
You do not need to remove the radiator hose, but you can unclamp it if you have trouble reaching the housing’s bolts.
If the housing has dents or pitting, you should also replace it.
6 Pull the old thermostat out with a pair of pliers. Check the port on your engine where you removed the housing to locate the thermostat, which looks like a cylinder with a metal ring around the outside and a pointed valve on top. If you don’t see the thermostat in the engine port, it may be stuck in the housing end with the hose. Grip the top of the thermostat with the pliers and pull it straight out. If the thermostat feels stuck, try twisting it as you pull it out.[5]XResearch source
Save the old thermostat until you get a new one or take pictures of it to ensure that you buy one that’s exactly the same.
Advertisement Part 2 Part 2 of 3:
Installing the New Thermostat
Download Article
1 Get a replacement thermostat and gasket with the same heat rating. Look around the thermostat’s ring for a temperature listing, which is when the thermostat opens and allows coolant to pass through the engine. Look at an automotive store for a thermostat that lists the same opening temperature, or else your vehicle may not operate properly. Then look for a thermostat gasket that matches the shape of the housing’s flange so the coolant doesn’t leak while your vehicle runs.[6]XResearch source
New thermostats and gaskets usually cost over $50 USD total, but it may be more expensive depending on the make and model of your vehicle.
The type of gasket you buy depends on the make and model of your vehicle.
2 Remove any residue from the housing and engine flanges with a scraper. Hold your scraper against the housing flange at a 45-degree angle. Use light pressure to scrape off the residue that was leftover from the old gasket. Keep cleaning the flange until it’s smooth. Then scrape the flange on the engine.[7]XResearch source
If you don’t clean off the residue, then the housing won’t sit properly and could cause coolant to leak.
Avoid being too forceful with your scraper since the thermostat housing is usually made from aluminum and can easily get damaged or dented.
3 Put the thermostat in the engine flange so the valve points up. Inspect your new thermostat to find the pointed valve on top and the spring on the bottom. Slide the thermostat into the port on your engine and push it in tightly. Make sure the thermostat’s ring fits perfectly in the port, or else coolant will be able to leak through.[8]XResearch source
If you install the thermostat with the spring side face-up, it won’t open properly and could cause your engine to overheat.
4 Line the new thermostat gasket up on the flange. Your gasket will look like a flat piece of plastic or rubber that’s the same shape as the flanges. Put the gasket on top of the engine’s flange and line up the holes. Make sure you don’t block any of the holes or ports, or else the thermostat won’t work properly.[9]XResearch source
Variation: Depending on your vehicle’s make and model, you may need to install a circular gasket directly on the thermostat instead of setting one on the flange. Fit the thermostat’s ring into the groove running through the middle of the gasket before installing the thermostat.
5 Bolt the housing back onto the engine. Set the housing on top of the gasket so the bolt holes line up. Turn the bolts clockwise by hand until they’re tight. Then use your ratchet to tighten the bolts until you feel resistance. Look up the torque specifications for your make and model of vehicle and only tighten the bolts by that amount.[10]XResearch source
Avoid overtightening the bolts since you could easily damage the aluminum housing.
Advertisement Part 3 Part 3 of 3:
Refilling the Coolant
Download Article
1 Pour coolant into the reservoir up to the fill line. Locate the plastic coolant reservoir near the side or back corner of the engine bay. Open the cap and pour in the coolant you originally drained into the drip pan. If the coolant was dirty, then look up the coolant specifications for your vehicle and get a new bottle in the right color.[11]XResearch source Keep pouring the coolant in until it reaches the fill line on the side of the reservoir.[12]XResearch source
If your vehicle doesn’t have a reservoir, pour the coolant directly into your radiator.
Warning: Vehicle coolant is toxic and can give off harmful vapors, so be sure to work in a well-ventilated area.
2 Screw on the radiator cap to seal it. Press the radiator cap back onto the opening on top of your radiator. Turn the cap clockwise to tighten it and seal the radiator so your coolant doesn’t splash or leak.[13]XResearch source
If you don’t put the cap back on, then the thermostat and radiator won’t function properly and your engine may overheat.
3 Start your vehicle’s engine to run coolant through the system. Turn the key in the ignition to run your vehicle’s engine. Leave the engine to idle for 5–10 minutes so the engine can warm up and activate your thermostat. As the engine runs, look at the thermostat housing to see if there are any leaks. After that, turn off your vehicle.[14]XResearch source
Check the temperature gauge on your dashboard to make sure it stays below the ¾-mark. If the gauge still goes into the red zone, then there may be a leak or you've installed the thermostat improperly.
4 Top off your coolant once your engine cools down again. Since the coolant will run into your engine and radiator, the levels may go down. Wait until your engine completely cools again so you don’t get burnt. Open the cap on the reservoir and check the coolant levels to see if you need to add more. Pour the coolant in until it reaches the fill line to ensure your engine doesn’t overheat.[15]XResearch source
Avoid overfilling the coolant reservoir since it could cause damage if pressure builds up.
Advertisement
Expert Q&A
Search Add New Question Ask a Question 200 characters left Include your email address to get a message when this question is answered. Submit Advertisement
Video
Tips
If you have trouble locating your vehicle’s thermostat or don’t feel confident making your repairs, take the vehicle into a mechanic to have it fixed. Thanks Helpful 3 Not Helpful 2
Submit a Tip All tip submissions are carefully reviewed before being published Name Please provide your name and last initial Submit Thanks for submitting a tip for review! Advertisement
Warnings
Always wait for your engine to cool down before you start working, or else you could get severe burns from the parts or the coolant.[16]XResearch sourceThanks Helpful 1 Not Helpful 0
Never drive your vehicle without the thermostat since your engine could easily overheat.[17]XResearch sourceThanks Helpful 1 Not Helpful 0
Vehicle coolant is toxic if ingested and can release harmful vapors.[18]XResearch sourceThanks Helpful 1 Not Helpful 0
Advertisement
Things You’ll Need
Drip pan
Ratchet
Pliers
Vehicle thermostat
Thermostat gasket
Metal scraper
Coolant
You Might Also Like
How toTell if Your Car's Thermostat Is Stuck ClosedHow toReplace a ThermostatHow toChange Radiator FluidHow toChange a Car RadiatorHow toFix a RadiatorHow toDiagnose a Cooling System ProblemHow toUnclog a RadiatorHow toStop an Engine from OverheatingHow toReplace a Leaking Radiator HoseHow to Flush a Car's Radiator Coolant SystemHow to Check Coolant Level & Add Coolant To Your Car10 Main Reasons Your Car Is Running Hot (and What to Do)How toTest a Temperature Sensor with a MultimeterHow toCheck Coolant Advertisement
Reviewed by: Jason Shackelford Auto Technician This article was reviewed by Jason Shackelford and by wikiHow staff writer, Hunter Rising. Jason Shackelford is the Owner of Stingray Auto Repair, a family owned and operated auto repair shop with locations in Seattle and Redmond, Washington. He has over 24 years of experience in auto repair and services, and every single technician on Jason’s team has more than 10 years of experience. This article has been viewed 124,023 times. 36 votes - 92% Co-authors: 8Updated: January 21, 2026 Views: 124,023 Categories: Car Maintenance and Repair In other languagesJapanese
Print
Send fan mail to authors
Thanks to all authors for creating a page that has been read 124,023 times.
Did this article help you?
Yes No Advertisement Cookies make wikiHow better. By continuing to use our site, you agree to our cookie policy. Reviewed by: Jason Shackelford Auto Technician Co-authors: 8Updated: January 21, 2026 Views: 124,02392% of readers found this article helpful. 36 votes - 92% Click a star to add your vote
Quizzes & Games
How Good Are My Survival Instincts QuizTake QuizWhat Tarot Card Am I QuizTake QuizWhat Is My Type of Girl QuizTake QuizWhat Chakra Do I Need to Balance QuizTake QuizAm I Smarter than a 5th Grader QuizTake QuizAm I Smart QuizTake Quiz
You Might Also Like
How toTell if Your Car's Thermostat Is Stuck ClosedHow toReplace a ThermostatHow toChange Radiator FluidHow toChange a Car Radiator
Featured Articles
How toMake a Paper AirplaneHow toLearn Morse CodeHow toFold an Origami Star (Shuriken)How to Fold and Use a Paper Fortune Teller
Trending Articles
What Female Body Shape Are You? How to Identify YoursWhat Emojis Mean Sex?What Pokémon Am I QuizDo I Have Brainrot QuizSigns a Woman is Sexually Attracted to YouFinish the Lyrics Quiz
Featured Articles
What Animal Am I QuizAm I Gay QuizHow Well Do I Know My Best Friend QuizAm I an Alpha, Beta, or Omega Quiz
Featured Articles
160+ Good Roasts to Burn Your Friends & Family MembersHow to Play the Snaps Guessing Game140+ Wavelength Game Categories & Questions to Extend Your PlayThe Ultimate Collection of Funny, Cheesy, & Romantic Rizz LinesVirtual Truth or Dare Questions to Keep Things Interesting180 Good Comebacks & Savage Roasts to Win Any Argument
Watch Articles
How toEat GuavaHow to Get Yellow Stains Out of White ShoesLeft Eye Twitching for Females: What Astrology Says About Eye Twitching50 First Date Conversation Starters to Spark a ConnectionHow to Make a Mask Out of Paper (for Kids or Adults)How to Put Jibbitz on Crocs
Trending Articles
Do You Agree with These "Hear Me Out" Character Hot Takes?How to Read Face Moles: Lucky and Unlucky PlacementsWhat JJK Character Am I QuizFade Hairstyle Types for Men: A Complete GuideRecessed Maxilla (Upper Jawbone): Symptoms & TreatmentCan Your Finger Length Tell Your Personality?
Quizzes & Games
Can You Spot The False Climate Claims QuizTake QuizTraffic Signs TestTake QuizAre My Hormones Imbalanced QuizTake QuizThe Impossible QuizTake QuizWhat Skin Type Do I Have QuizTake QuizHow Will I Die QuizTake Quiz
Categories
Cars & Other Vehicles
Cars
Car Maintenance and Repair
wikiHow Newsletter You're all set! Helpful how-tos delivered toyour inbox every week! Sign me up! By signing up you are agreeing to receive emails according to our privacy policy.
Home
About wikiHow
Experts
Jobs
Contact Us
Site Map
Terms of Use
Privacy Policy
Do Not Sell or Share My Info
Not Selling Info
Contribute
Follow Us
×
wikiHow Tech Help Pro:
Develop the tech skills you need for work and life
Download Article Co-authored by Hunter Rising Reviewed by Jason Shackelford 
Advertisement 
Reviewed by: Jason Shackelford Auto Technician This article was reviewed by Jason Shackelford and by wikiHow staff writer, Hunter Rising. Jason Shackelford is the Owner of Stingray Auto Repair, a family owned and operated auto repair shop with locations in Seattle and Redmond, Washington. He has over 24 years of experience in auto repair and services, and every single technician on Jason’s team has more than 10 years of experience. This article has been viewed 124,023 times. 36 votes - 92% Co-authors: 8 Updated: January 21, 2026 Views: 124,023 Categories: Car Maintenance and Repair In other languagesJapanese 
Take Quiz
Take Quiz
Take Quiz
Take Quiz
Take Quiz
Take Quiz 
Take Quiz
Take Quiz
Take Quiz
Take Quiz
Take Quiz
Take Quiz 
595 
1 Wait for the engine to cool down if you drove recently. As you drive your vehicle, the coolant running through the engine heats up and could cause severe burns. Before you make your repairs, give your vehicle 30–60 minutes so it can cool off. To check the temperature, open the hood and lightly touch your engine to see if it feels hot. If it’s cool to the touch, then you can work safely. 
2 Take the cap off of your radiator. Locate your radiator, which is a long black box under your hood and in the front of your engine bay directly behind the grille. Look for a circular cap on top of the radiator and turn it counterclockwise to loosen it. Set the cap aside while you’re working so you don’t misplace it.[1] 
3 Put a drip pan underneath your radiator’s drain plug. Look underneath your vehicle at the bottom of the radiator and look for a small plastic wingnut or plug. Slide a drip pan directly under the plug so your coolant doesn’t spill everywhere or make a mess while you’re working.[2] 
4 Drain half of the coolant out from your radiator’s drain valve. Turn the drain plug on your radiator counterclockwise until you see a steady stream of coolant pour into the drip pan. Check the levels of the coolant by looking into the radiator. You only need to remove enough coolant to expose the thermostat, so once half of the coolant flows out from the plug, turn it clockwise to tighten it again.[3] 
5 Unbolt the thermostat housing from the engine block with a ratchet. Follow the hose from the top of your vehicle’s radiator to the side of your engine. Where the hose connects to the engine will be the housing for the thermostat. Find the 2 bolts on each side of the housing’s flange and turn them counterclockwise with a ratchet. Once you loosen the bolts, you can easily lift the housing up to detach it from the engine.[4] 
6 Pull the old thermostat out with a pair of pliers. Check the port on your engine where you removed the housing to locate the thermostat, which looks like a cylinder with a metal ring around the outside and a pointed valve on top. If you don’t see the thermostat in the engine port, it may be stuck in the housing end with the hose. Grip the top of the thermostat with the pliers and pull it straight out. If the thermostat feels stuck, try twisting it as you pull it out.[5] 
1 Get a replacement thermostat and gasket with the same heat rating. Look around the thermostat’s ring for a temperature listing, which is when the thermostat opens and allows coolant to pass through the engine. Look at an automotive store for a thermostat that lists the same opening temperature, or else your vehicle may not operate properly. Then look for a thermostat gasket that matches the shape of the housing’s flange so the coolant doesn’t leak while your vehicle runs.[6] 
2 Remove any residue from the housing and engine flanges with a scraper. Hold your scraper against the housing flange at a 45-degree angle. Use light pressure to scrape off the residue that was leftover from the old gasket. Keep cleaning the flange until it’s smooth. Then scrape the flange on the engine.[7] 
3 Put the thermostat in the engine flange so the valve points up. Inspect your new thermostat to find the pointed valve on top and the spring on the bottom. Slide the thermostat into the port on your engine and push it in tightly. Make sure the thermostat’s ring fits perfectly in the port, or else coolant will be able to leak through.[8] 
4 Line the new thermostat gasket up on the flange. Your gasket will look like a flat piece of plastic or rubber that’s the same shape as the flanges. Put the gasket on top of the engine’s flange and line up the holes. Make sure you don’t block any of the holes or ports, or else the thermostat won’t work properly.[9] 
5 Bolt the housing back onto the engine. Set the housing on top of the gasket so the bolt holes line up. Turn the bolts clockwise by hand until they’re tight. Then use your ratchet to tighten the bolts until you feel resistance. Look up the torque specifications for your make and model of vehicle and only tighten the bolts by that amount.[10] 
1 Pour coolant into the reservoir up to the fill line. Locate the plastic coolant reservoir near the side or back corner of the engine bay. Open the cap and pour in the coolant you originally drained into the drip pan. If the coolant was dirty, then look up the coolant specifications for your vehicle and get a new bottle in the right color.[11] Keep pouring the coolant in until it reaches the fill line on the side of the reservoir.[12] 
2 Screw on the radiator cap to seal it. Press the radiator cap back onto the opening on top of your radiator. Turn the cap clockwise to tighten it and seal the radiator so your coolant doesn’t splash or leak.[13] 
3 Start your vehicle’s engine to run coolant through the system. Turn the key in the ignition to run your vehicle’s engine. Leave the engine to idle for 5–10 minutes so the engine can warm up and activate your thermostat. As the engine runs, look at the thermostat housing to see if there are any leaks. After that, turn off your vehicle.[14] 
4 Top off your coolant once your engine cools down again. Since the coolant will run into your engine and radiator, the levels may go down. Wait until your engine completely cools again so you don’t get burnt. Open the cap on the reservoir and check the coolant levels to see if you need to add more. Pour the coolant in until it reaches the fill line to ensure your engine doesn’t overheat.[15]