7 Common Symptoms of a Bad or Failing Thermostat

Common signs and symptoms of a bad engine thermostat and how to test if it has failed.
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Symptoms of a Bad or Failing Thermostat.
High temperature readings (Engine Overheating).
Not heating up when weather is cold.
Coolant fans stay on constantly.
Erratic changes in temperature.
Unusual noises.
Coolant Leaking .
Heater problems.
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[@xdsmastermia]

Thanks for the info, my car was acting strange gurgling, now i know why. It overheated

[@Nsadheo]

Thanks man

[@thetwogardens6048]

Very well done Explanation. !

[@tr9478]

Great info thanks

[@TheManRalphy]

Great video thank you

[@midasracer]

When the fan is on all the time it means the fluid in the rad is hot since the switch for the fan is on the rad. This could mean the thermostat doesn't open properly and coolant flow is limited. But could also be a blocked radiator.

[@davianceable]

ikr lived that ,they blame the radiator changed it it gets hotter than before than changed thermostat because it was behind the timing belt so changed it lastly and all my problems gone away the thermostat they remove is like new no rust nothing but it was faulty ,so the lesson ı learned change it every 7 years if it is clean or rusted no matter .

[@mykidsafag]

Can a new thermostat be bad ? Exterra pushes the coolent out the resavior after it warms up to normal temp

[@davianceable]

@@mykidsafag every part can come faulty but consider the possiblity of early sign of head gasket fault which is exhaust gas escaping into coolant and pushes out of resorvoir and makes coolant boil ,but pressured systems like german cars shouldnt be used without resarvoir cap or it boiling and escapes out of it ,and it is normal to pressured coolant systems to squirt some of coolant from cap bleeder when it needs to but if you lose more than you supposed to be you should check it.

[@heatherlohbeck4412]

​@@mykidsafagis the gasket there

[@kevin_edinofficial]

Yes but… al engines doesn’t have the switch in the radiator, some have dem in the block, in the thermostat housing etc.

[@kalpeshkapadia4623]

Thanks sir

[@Mruiz0085]

My heater runs good when driving but not on idle and my temperature gauge reads cold would you say that it is the sensor not the thermostat?

[@paulatuf1019]

Chrysler 300 2.7 I had the water pump, timing chain, thermostat & reservoir replaced. The vehicle overheats & and the coolant leaks out the reservoir. The mechanic recommends replacing the radiator. What do you think? Thank you

[@shaijugm]

my car mrg not showing only less heat and in in hot wether like noon i shows more temperature , let know is it thermostats problem ?

[@saren6538]

My dispatch van takes a while to heat up in the winter and then it overheats only at speed 40mph plus when I put the heating on the overheating needle starts to come down again.. thermostat ?

[@fuzion_nova4512]

Could it mean a bad gasket if I’m pouring anti freeze in my system and it leaks but also bad heat?

[@jessefoster8987]

2016 buick encore 1.4. It was 22 degrees out today. The car took forever to warm up at idle. While driving it she warms up all the way. Then parked and idled and temp gage went down a cpl slashes. What would cause this.

[@PedroRodriguez-hy5ty]

How about if your living in a warmer climate let me know thanks

[@FreddyMarothi]

Hi rounalt cleo does have a termostart or not that question is that i have a rounalt cleo 2013 and said stop after said engine filler hazard

[@Spong-ly4ck]

Thanks G i was so scared i had a blown head gasket lol

[@chemeofficial]

That’s exactly what I think I got rn😂😂😂😂

[@vayci]

Bro, if you don’t take the top of your block off and go stick a $20 gasket on it from AutoZone I’m gonna slap you😂

[@vayci]

It’s really not that hard. Hey, there’s videos on how to do it and be there’s this really nice thing called a Haynes repair. Manual works absolutely wonders based off of the original owners manual just more in-depth based on complete tear down and rebuild you’re welcome

[@heatherlohbeck4412]

A blown head gasket is gonna make your car sound like shit

[@heatherlohbeck4412]

​@@vayciabsolutely bro. It used to be Chilton's but now it's Haynes

[@D3busCollects]

Could it affect the electric power steering?

[@dewyazzie980]

The gurgling noise heard is that when vehicle is on or off?

[@laffattemckissick9693]

I have a 2006 Malibu 3.5 i replaced the thermostat and its still stuck closed.i also replaced my coolant temperature sensor and coolant wont circulate why? please help and thank you

[@user-wu2mb2nw3u]

I am using Lexus ES 300! I change my radiator but since then my temperature will raise above normal and drop back to normal but during the hot wealth/long distance journey, Temperature will raise above normal and fall to normal several times till it’s raises above normal and never return back. I have taken it to different mechanics and electricians but the problem still surface . What might be the problem ?

[@shellybelle6781]

My heating working. It’s not over heating. What should I do?

[@JohnSRay-en7pi]

what is bad about running a diesel engine cooler than normal because of open thermostat ?

[@dalegribble8140]

You can also have a lazy thermostat even thought the thermostat opens

[@tortugalisa4748]

Hi @HVAC Mechanic! My dad has long passed away, my big brother recently passed away and my older son that knows a little about cars is too busy with his junk hauling buisness on the weekends and a full time job during weekdays so I am on my own as a 54 year old disabled single mom so I would like to ask you a question about my 2004 chevy silverado 2500 HD 6.0 - Driving to work at 2am, temp outside being about 27°, about 8 minutes into my drive, I hear a not so loud pop, billowing steam out the front and sides for a good 3 minutes, the truck shut off so I rolled it to a stop on the side of the road and coolant leaked onto the ground. I did not have time to check it out as I called my older son to come take me to work. We towed it back to my house in the morning. I was curious to see if it would start and how it would sound, also I had to back it into my driveway and it started right up and sounded fine. Of course I only ran it for about 20 seconds just to back it up and I shut it off so I wouldnt cause any further damage. My son did borrow my truck for 8 months prior for his junk hauling business and upon returning my truck he did mention he thought he noticed it starting to overheat from time to time in those months and pointed out a drippy leak at the top of the radiator connection line. Could you please point me in a direction I can take so I can try to fix my truck. Its been sitting for 2 months now and I finally got my taxes back to afford parts I need- Thank you so much for your time HVAC Mechanic😊👍

[@HVAC_Mechanic]

It's hard to say what the cause is, but I would start by inspecting the radiator and hoses for any leaks and then checking the water pump and thermostat.

[@tortugalisa4748]

@@HVAC_Mechanic Will do! Thanks for the response👍

[@ericrachoene9134]

My polo vivo shows water sign warning,but water bottle is full of water....whats the problem

[@pro0055]

Hi, I have a 2012 Chevy equinox and it started acting weird the other day The temperature gauge is always stuck on cold now even after running the vehicle for several minutes and the fan stays on for 5 to 10 minutes after the vehicle has been shut off I haven't heard any weird noises or gurgling noises or have any leaking fluid this just started 2 days ago before that everything was fine could this be because of a faulty thermostat or am I looking at a more serious issue?

[@HVAC_Mechanic]

I would test the coolant temperature sensor.

[@ahotdj07]

@2:00 - I have a 2012 Honda Accord V6 EXL 3.5l. I will be driving and the car temperature will be at 165 degrees - then suddenly, the gauge drops from being in the middle to at cold. The temperature also drops to about 120 degrees. Then after a few minutes, it will go back up again. Could this be a bad thermostat?

[@HVAC_Mechanic]

Are there signs the engine is overheating? Otherwise, it may be a bad engine coolant temperature sensor.

[@ahotdj07]

@@HVAC_Mechanic no it’s not. I did hAve the thermostat replaced and it hasn’t dropped since.

[@yolandaortega6538]

Question: I changed the thermostat on my Acura MDX 2005 because the fan doesn't turn on until the I car is off... do you think it could be the coolant temperature sensor?

[@HVAC_Mechanic]

A bad ECT or bad wiring can cause that issue. Does the dashboard gauge work correctly? If you have a scan tool, check to see if the ECT is reporting a temperature that is way off.

[@user-np2jo9sm3l]

My overflow is leaking fluid daily and multiple times a day, also my fan comes on and off at different times, which is causing my 2029 jeep renegade to overheat. What is my cause, somebody said it's my radiator, but I am having doubts

[@nuttietrendchannel4265]

Hi, could a bad thermostat affect AC performance? I have 120k car, never had thermostat and water pump replaced. But my AC recently taken about 5 to 6 minutes to click on. If on a cold day, the AC won't even work at all even turned on for awhile.

[@SummerEazelivin]

Have u checked ur cabin air filter? Usually during oil changes the mechanic swaps out the dirty air filter for a new one. Also check the fan if it is broken or not responding.

[@chogaf5156]

Hey my radiator fan wont work I remove the plug to the coolant temp sensor and the fans turn on I plug the coolant temp sens back in the fans stay on I pull the fan relay out the right fan turns off and the left fan stays on I turn the car off and on again and the fans won't turn on anymore my ac won't work aswell .....would a bad thermostat be the cause of this ??

[@HVAC_Mechanic]

Is the engine overheating? If the engine is not overheating, the temp sensor may be bad.

[@freebird8886]

What if when you squeeze the hose its real tight cant really squeeze it 🤔

[@jeovanicontreras409]

There’s probably a spring in there

[@americanvikinggsd4631]

Generally that means the hose is under pressure. Don't open the cap until it cools down.

[@craig9843]

In my 2019 Toyota RAV4 the temp gauge goes to normal after 3.5 to 4 miles but then drops down lower then shortly goes back to normal and then it’s fine. Any ideas? I had a dog run into the front of my thanksgiving night and did some bumper damage passenger side front also my cousin that does auto body repair mentioned the a/c has damage and you can visibly see that. Maybe the radiator has damage? But it never goes above normalI don’t know yet, the car hopefully will be repaired next week.

[@HVAC_Mechanic]

If it is not overheating, I would check the engine coolant temperature sensor.

[@craig9843]

@@HVAC_Mechanic thank you

[@seanb4459]

My coolant gauge doesn’t read hot my heat is working, but I’m having steam come out of the front of the car with a very small leak and pressurized. What could it be?

[@nicholasfurst]

Steam is common with heater core issues

[@Berto3.7]

My temp gauge is still on high after a couple of hours I haven’t used the car and the needle is still in the same area I turn the car on the fan turns on then stops any idea what it is because the engine isn’t hot or anything the needle just high could it be the thermostat?

[@HVAC_Mechanic]

If the engine is not overheating but the gauge is reporting it is, the coolant temperature sensor is likely bad.

[@johnthompson9893]

2019 malibu fans are working really hard tempature is normal half way but when I cut the car off fans stay on for about 10mins then cut off

[@christiansilva1296]

Temp garage takes forever to get into its normal place dose not over here but dose go down then come back up to the normal spot slowly, also having heat on the passenger side not the driver

[@jennifercombs6709]

I have a vw Jetta Hybrid that's doing the same exact thing. I'm also smelling a gas odor when I first start my car. Idk I'm a single momma trying to figure this all out. Don't have money for a shop. 😢😢

[@SosaGaming27]

​@jennifercombs6709 that's you're problem lol Volkswagen

[@mrme9517]

HEATER CORE CLOGGED OR BAD T STAT BLEND DOOR OR BLEND DOOR ACTUATOR DOESN'T HURT TO CHANGE THE CAP EITHER HOPE THAT HELPS

[@davidjustdavid]

​@@jennifercombs6709 🎶 🎻 🎵

[@mitchellfleming8658]

What if you change it like 3 time? What's make the thermostat goes bad?

[@HVAC_Mechanic]

If there is a lot of rust in the system, it can cause them to fail quickly.

[@tortugalisa4748]

🌟New Subscriber🌟

[@demondtedickerson7928]

My temperature gauge goes up to normal level but every time I smash the gas it goes up dramatically what’s the cause of that anyone knows?

[@west_park7993]

how high? did you find the cause? did you fix it? I used autel to watch temp and pump revs. see my other post.

[@kennethmarcano2532]

What if my fan don’t turn on when the car go above normal temperature?

[@poker345611]

Temperature sending unit.

[@west_park7993]

and when the fans are off all the time? and temperature reaches 101? the fans and relays are OK, because when I push the AC on, fans begin to operate.

[@kevinhancock4064]

Did u solve it ? My car is loke this ..I had changed the ect but I now own an oem 1 to put in and go from there

[@west_park7993]

@@kevinhancock4064 no, i did not find the cause. I had random unpredictable overheating. very short ones, 2-3 sec each. changed pump and rotor, changed thermostat, changed ETC. finally toyota diagnosed failing head gasket. i did not want to believe it is hg, because i took good care of my car, never low on water, never late for oil. but them faced the reality, i changed the HG. DO NOT buy original toyota head gaskets: some of the lots are substandard, thats why they fail. i got mine from rockout, victor reinz. i finished, put it together, and started driving as a test round town, while watching realtime temperature and pump revolution. so, first 20-25 miles temp was 85-88 degC. then suddenly raised up to 101. i freaked and overreacted and stopped. so, I took apart the cooling system, and flushed both radiators with garden hose. Expected to see deposits, mud, sand, but nothing came out. Then I reinstalled the old original thermostat. Put it together, and no problem. Just put 950 miles on new head gasket. No leaks, no error DTC. I drove 750 miles in one day while watching the temperature: ROCK SOLID, 88-89 C. Pump revolutions: 2500-2600, and when you rev engine, goes to 3000. So, I suspect that the new thermostat may have turning bad in 6 months. I returned the old one, cause it was proven to be good. I also changed the ECT, and checked the old one. he old one was OK, I think. It is Pt, platinum wire, because Pt is extremely durable. no oxidation, very high melting, encapsulated in a seald copper ampule. I checked the resistivity of the old one, it was 1500 ohm at room temperature, this is what it should be. You can find tables with T-R relations on the internet.

[@pamelaadams9337]

I just had my radiator replaced. Now, I have no heat. I returned my car where the radiator was replaced. I was charged $10.00. I was told a diagnostic test was needed to further investigate the issue. I declined. Does the radiator have anything to do with the function of the heat?

[@michelefreeny3195]

YES

[@zillogullu33]

So you declined to pay 10 dollars to check something that could cost you thousands ...Penny wise and Pound foolish smh.

[@Werk4Cash]

Wtf why did you decline a 10 dollar service fee?

[@DAGREATBOOG]

Heater core probably

[@AboriginalSon74]

She was upset y’all

[@myangelmmm1]

My car overheats , have to run the heater even during Summer

[@jimbolyard4889]

If you're car ever runs hot best to change theremosat

[@JRichardGaming]

My car only overheated after the coolant leaked out the radiator

[@haunguyen543]

The way you teach as sell at auction car. Too bad no clear

[@user-wu2mb2nw3u]

I am using Lexus ES 300! I change my radiator but since then my temperature will raise above normal and drop back to normal but during the hot wealth/long distance journey, Temperature will raise above normal and fall to normal several times till it’s raises above normal and never return back. I have taken it to different mechanics and electricians but the problem still surface . What might be the problem ?

[@user-fo9gt5ri8f]

Man having a similar problem did you find anything out