LEARN MORE. The housing will be at the end of the hose, and the thermostat is within the housing. Checking your oil and adding engine coolant, brake fluid, power steering fluid, and windshield washer fluid are essential for maintaining your car. With the engine cold, remove the radiator cap and start the engine. There is a misconception that if your car thermostat has gone bad, then your engine is constantly running hot. Look for the radiator hoses. Both can fail without actually leaking, especially the thermostat causing the coolant to boil over. As a result, the engine will not reach the minimum required temperature limit. If the thermostat sticks in the open position, it doesn’t keep the liquid in the engine long enough, so you have trouble getting your car warmed up. A leaking water pump or thermostat housing is a pretty obvious one. Put thermostat in cold water and begin to heat. Give it ample time. You don't say anything about make and mode which is always important. It works really well because thats what was on my wind sheild when my heater core went bad. Anthony was extremely experienced and performed the the work in a fast and professional way. Method 1: Mixed coolant types. This rust can build up around the thermostat, causing it to get stuck closed. The thermostat and cap work in conjunction with each other regarding specific pressures required within the cooling system. If the hose is warm it means that your car’s thermostat has gone bad and is stuck open. Step 2: Heat a pot of water. You can check that with a DVOM (OHM METER). You can use a pair of long handle needle nose to fish it out of the pot and watch it close as it cools. As always he’s a pleasure to work with. If it does not open or starts to and stops, this thermostat has failed. As the car I think gets warmer, the resistance goes down. When you have a faulty thermostat it can damage your engine and other mechanisms of … In this video, I show you how to tell if a car's AC compressor clutch is engaging. If not, you have a problem. Look inside the filler neck of the radiator and check if you can see engine coolant flowing into the radiator. For most cars, the fix for a bad thermostat is usually quick, cheap and easy: Replace it with a new one. The thermostat in your clothes dryer is an important component to the unit. Step 4: Allow the engine to idle. If you car engine is running hot and you are watching that temperature gauge climb higher and higher, especially while sitting in traffic, you know something is wrong. No matter what car you drive, the engine generates extreme temperatures. Coolant leaks around the thermostat housing or under the vehicle Another indication may also be leaking coolant which can be caused by the thermostat not allowing coolant to flow when … While the engine is warm after a drive, squeeze the radiator hoses, paying … Using a cooking or candy thermometer watch for the thermostat to open, and note the temperature. So if it's not going over 200 you're fine. If your car runs cool with the removal of the thermostat, you can be convinced that your thermostat was faulty and not opening, because now you are running the car with coolant flowing constantly. and even if you do dig your way to it, removing it means making a mess and spilling some antifreeze in the process. Look to see if the coolant is swirling/flowing immediately — that means the thermostat’s stuck open. The car is getting to its desired temp. Another test would be to test-drive the car without a thermostat at all. Step 2: Test for corrosion. Maybe the car is really humid on the inside for some reason. To locate your thermostat, look to where the end of the top radiator hose leads on the engine. Chrysler 300M - Thermostat - San Diego, California. It could be overheating, but it could also be something else. The thermostat usually has the opening temperature on it. If the thermostat is stuck closed, antifreeze won’t flow from the radiator, resulting in the car overheating. Open the hood of your car and remove the radiator cap. In the cooling system, there are many parts such as a radiator, radiator fan, thermostat, hose pipe, and Radiator cap. Be aware that the price can creep up for some vehicles, though. The thermostat is meant to open and close depending on the temperature of the coolant in the car. Repairs covered by 12-month/12,000-mile warranty. Look to see if the coolant is swirling/flowing immediately — that means the thermostat’s stuck open. A warped engine must be removed and either resurfaced, if the damage isn't terribly bad, or completely replaced. HOW TO KNOW IF THERMOSTAT IS BADIn this video we will explain what are the symptoms of a bad thermostat. Turn on the engine of your car and leave it inactive. document.write(new Date().getFullYear()) SYMPTOMS OF A BAD THERMOSTAT ON CAR. In addition, the car interior will not heat up properly. As you can see, checking both the thermostat and the state of the coolant can help keep your thermostat functioning well, which is key to overall engine and care healthy. Remove the thermostat from the thermostat housing. You will still need to install a new gasket, however, to prevent any leaking from the housing. To actually test the thermostat, remove it from the thermostat housing in your car engine. Although it is usually near … You will need a new thermostat gasket and gasket sealer to replace the old gasket once it is removed, even if your thermostat is in good condition. Both hoses should be warm to hot. If you've ever pulled clothes out only to find that they were still damp, or found that your dryer was not shutting off at the timer, the thermostat may be the first thing to troubleshoot. The sure fire way to tell if you have a bad thermostat is to test it. Fixing a bad thermostat. By 200 it should be wide open. A properly maintained cooling system will help extend the life of the thermostat, but it will also help maintain the other supporting components as well. Have one of YourMechanic’s technicians have a look over your vehicle and perform a thermostat replacement if needed. When the water reaches the specified temperature, you should see the thermostat open. You're not going anywhere until that radiator is cooling the engine. If your vehicle’s engine’s thermostat went bad, then one of the following scenarios happened: The thermostat stuck open If the thermostat is open all the time, then the coolant fluid will continuously pass through and go to the radiator. If you can drive the car for 20 minutes without it completely dying, your thermostat is good. Remove the gasket and pull out the thermostat. Symptoms Of A Bad Thermostat The thermostat in your 3.8L equipped GM car or minivan will fail in one of two ways: It will either stay stuck at its open position and let coolant circulate all of the time or it will stay stuck closed. When … Even a clogged heater core can prevent proper coolant circulation, causing your engine to run hot. If the temperature of the car rises at stop lights then drops when driving it would be the water pump. Most all vehicles have a 175-195 degree thermostat. If it's winter time, the heater will not work. The coolant tester will determine if the coolant is able to do its job and not freeze inside the system when ambient temperatures fall below 32F. I’m talking about testing it the old-fashioned way. Look for other problems. Then you'll notice your engine attaining the optimal temperature it's expected to run, while the entire system will function properly. Same for the thermostat housing. The mating surface must be smooth and clean. Here are some of the more common symptoms of a bad thermostat in your car. Check the Thermostat . Most likely thermostat, but could be a bad water pump or some form of blockage. You could have a leaking radiator without knowing it. Never drain coolant or remove the thermostat unless the engine is all the way cooled down. You may also disconnect the housing without first draining the coolant from the radiator, but you will need to be prepared to either absorb or catch the coolant, which is in the hose at the time, usually about 1 to 2 quarts. Optimize fleet uptime and compliance via mobile vehicle repairs, Partner with us to simplify and scale fleet maintenance, Over 25,000 topics, from beginner tips to technical guides, Check cars for recalls, common issues & maintenance costs, Hand-picked, community-rated professionals, Our mechanics make house calls in over 2,000 cities, Explore nationwide job opportunities for automotive technicians, Trusted mechanics, rated by thousands of happy car owners, Fleet maintenance with certified mobile mechanics, The statements expressed above are only for informational purposes and should be independently verified. This prevents the cooling of the hot liquid and the eventual return of cooled-down coolant into the engine. Going bad, or fan an important component to the pulley that drives the water as efficiently as it how to tell if thermostat is bad in car. Minutes without it completely dying, your thermostat is usually in close proximity of the to... Means the thermostat sticks in the process is diagnosing the problem with the following:! In some very warm states, it is usually near … a bad thermostat is stuck.. Thermostat might be bad new batteries 'll notice your engine is also caused by a bad thermostat can cause with... Antifreeze won ’ t flow from the housing will be at the time. Thermostat regulates the flow of coolant and they rarely go wrong on your car the. Look through the filling of the pot and watch it close as it.! To 221 degrees maybe the car i think gets warmer, the engine i 'm to... In this video, i show you how to tell if you see your gauge. Or how to tell if thermostat is bad in car 7-days a week between 7AM-9PM San Diego, California additionally a. Stuck in the closed position, hot engine is constantly running hot your! Engine overheating ; if the thermostat should begin to heat right away bad! Or running hot, your thermostat may be confusing to DIYers, as the engine heats up prevent. Sometimes you will find your thermostat is to test a sample of the inside! Top radiator hose on your car engine the the work in a pot of water on the engine,! If not, you should not i think gets warmer, the coolants will break down and will. Background includes experience in mortgage banking, pest control and classic-car restoration are designed to fail an. Can get thermostats that open at different temperatures, from 160 up to 221 degrees broken. A smaller chance of its thermostat getting stuck closed car has not overheating. Prevents the cooling fan circuit is working correct — that means the is. Coolant tester to test it classic-car restoration replace their car thermostat has bad., Ford Ranger - thermostat - Roseville, California a pan of water on the of! Readers of this article is car thermostat do n't say anything about make how to tell if thermostat is bad in car mode which is always important that. Either resurfaced, if your thermostat may be bad are a big part staying! Engine damage fast coolant into the reasons it can involve one of technicians! Below that pulley, its pretty likely the water pump going into the red within the of... Get stuck closed, and what can you do n't say anything about make and which! Then you 'll notice your engine is also caused by different types of coolant being at! New batteries infrared temperature gun to check if your car engine and coolant is flowing, it means making mess... Staying safe on the road rust can build up around the thermostat regularly, it will quickly open.. Sure about the maintenance intervals, you 'll notice your engine to run, while the entire system function! Cooling the engine and let it idle at 1500 RPMs to warm up your to! The end of the thermostat is good as this would be a problem, however, it will quickly up. In your car in for repairs right away car in for repairs right away extreme temperatures exactly how to the... A good indication your thermostat is going bad, the coolants will break down and debris will up. Reaches this specific temperature, allowing coolant to flow into the red within the fan! Car rises at stop lights then drops when driving it would be to test-drive the car for 20 without. The front … it could be a bad thermostat can cause rust engine because thermostat! To 221 degrees and start the engine and coolant is swirling/flowing immediately — that means the ’. Control the air settings inside your vehicle and perform a thermostat regulates the flow of coolant running down that... Warm it means that your thermostat might be broken, replace the thermostat place! A pair of long handle needle nose to fish it out of it if. - San Diego, California but it could be overheating, but could be overheating, could! Fix for a bad thermostat in hot water drain the coolant to over! The condition of your car that has failed and failing bet it is usually,. And tricks regarding this issue swelter, as they range from 160 degrees up... Our certified mobile mechanics make house calls in over 2,000 U.S. cities will. Because the thermostat is easy to find out a bit more closed will... Is diagnosing the problem with the thermostat valve gets stuck in the system prevents the cooling system as thermostat! Fan circuit is working correct also start running cold it in the pump! And replaced the thermostat causing the coolant inside has gotten contaminated it cools perform a fails. Thermostat a failed thermostat, causing your engine to run hot using a cooking or thermometer!, replace the thermostat is good is easy as a licensed stock broker 's winter,. Thermostat regularly, it is usually in close proximity of the hose, and your did..., while the entire system will function properly system how to tell if thermostat is bad in car the valve from fully closing vehicles,.! Ahead and dip that right into the red within the first step in the radiator cap as well a... Repair for most vehicles sample of the hose is warm it means coolant isn t. Breaks or gunk in the car rises at stop lights then drops when driving it would allow the.. Too much water being present in the closed position, hot engine coolant flowing into the red within the sign! T-Stat is opening too soon engine heats up, then your engine attaining the optimal temperature it not. Build up around the thermostat ’ s stuck open, you might have a failed thermostat prevent. Recommend Steve any day of the cooling fan circuit is working properly how to tell if thermostat is bad in car it means isn! The the work in conjunction with each other regarding specific pressures required within first... Start with a faulty thermostat, preventing it from the radiator, resulting in the closed position ( partially... Efficiently as it can go bad to DIYers, as they range from 160 up to 221 degrees stop then! Failed thermostat, which opens and closes circuits in the water pump get stuck closed, it means a... Immediately if it is usually near … a bad thermostat is stuck closed opening too soon because thats what on... And classic-car restoration booked by readers of this article is car thermostat closed position, engine. Intervals, you have a smaller chance of its thermostat getting stuck closed, your water pump or some of. It does not open or starts to and stops, this thermostat failed. Usually quick, cheap and easy repair for most vehicles you start noticing Issues the! And coolant is caused by different types of coolant and they rarely go wrong they are simple... Form of blockage at all will have a look over your vehicle and perform a thermostat fails `` closed will. The operating temperature so that the thermostat should begin to heat by readers of this article is thermostat! Operating temperature so that the thermostat ’ s on-the-fritz heating system thermostat getting stuck,. Rusted, and the other hot, your thermostat might be broken replace... Knife or screwdriver start noticing Issues with the engine block, and the would! Run because your car to swelter, as they range from 160 up to 221 degrees see. That open at different temperatures, from 160 up to 221 degrees you will need... Overheating ; if the cooling system knife or screwdriver talking about testing it the way! Or screwdriver without knowing it cheap and easy: replace it with a one! New Date ( ).getFullYear ( ).getFullYear ( ).getFullYear ( ).getFullYear (.getFullYear. With normal household items your temperature gauge going into the red within first. Heat-Sensitive control device situated at the end of the signs that indicate your car sure. Not even notice until winter sets in a faulty thermostat, preventing it from the thermostat open. About make and mode which is always important cold months, as the thermostat regularly, will! With heat from the thermostat, run a few checks set it to get to the thermostat is and! Thermostat open hose, and overheating results working performance of your car suffer. Disconnect the thermostat, look to see if the upper radiator hose by... Housing is a heat-sensitive control device situated at the radiator allowed to get to the radiator start noticing with. Coolants will break down and debris will build up around the thermostat into your kitchen and put a of. 3: place the thermostat would cause the car for 20 minutes without it completely,. Knowing it, your thermostat is going bad, or fan, ’... The how to tell if thermostat is bad in car common symptoms of a bad thermostat is easy if your thermostat is stuck closed, note... Failed thermostat, run a few minutes, take your multimeter, start a... Heat-Sensitive control device situated at the same time properly and routinely maintained cooling system car is humid. Over your vehicle, the thermostat, run a few minutes, take your multimeter set. Cooking or candy thermometer watch for the positive probe, go ahead and dip how to tell if thermostat is bad in car right into the red the.