Why Is My Car Overheating in the Winter?

Why is my car overheatingThere is no worse time to breakdown than in the winter.  When your car isn’t working like you expect it to it is always frustrating but add being cold to that and you’ve got a really bad day.  Even if you’re a weekend mechanic working on a car with frozen fingers is never enjoyable.  Worse yet if your car leaves you stranded, sitting in the cold hoping the tow truck shows up soon can feel like an eternity.  That is why it is extremely important to make sure that your vehicle is running properly during the winter months.

Maybe as the summer and fall have gone on you’ve noticed small things wrong with your car.  Things like lights not working or windows not shutting all the way.  Maybe you’ve got a check engine light that has been on and you’re hoping it’s nothing.  Or maybe you’ve got a temperature gauge that is wandering around and you’re hoping that as the weather gets colder your car will stop overheating.

The reality is that colder temperatures really won’t help your vehicle’s overheating problem and you will find yourself still asking, why is my car overheating?  Your car may be overheating for a variety of reasons, so it’s best to try and understand where this extra heat comes from before we move onto a solution.

The engine in your vehicle can be classified as a heat engine, meaning it turns heat into mechanical work.  The heat comes from the combustion process of fuel and air.  This heat then causes the gases in your cylinder to expand rapidly pushing against the piston in your engine forcing it to the bottom of the cylinder.  The crank shaft in your engine turns this motion of your piston into a rotational force which turns your transmission, axles, and consequently wheels.

Unfortunately the engine in your car cannot turn all of the heat produced by the combustion process into mechanical energy.  This extra heat that cannot be used is called waste heat and is removed in a variety of ways.  As the exhaust gases are pushed out of the chamber, they carry a significant amount of the waste heat with them.  Also, as the cool intake air enters your engine it will absorb some of the waste heat as well, especially in the winter.  For engines used in vehicles today, there is even more waste heat than can be removed through the exhaust gas and intake air so your vehicle’s cooling system is used to remove the rest of the waste heat.

If your vehicle is overheating it is because the waste heat created by the combustion process is not being entirely removed by these 3 methods so your engine heats up.  It is possible that your engine’s combustion process is creating more heat than usual, but that is unlikely in today’s fuel injected vehicles with electronically controlled ignition timing.

It is also unlikely that much has changed in your vehicle’s intake air or exhaust gases’ ability to cool your engine unless you have a significantly clogged exhaust system, so most often the problem lies with your vehicles cooling system.  Your vehicle’s cooling system is comprised of a few simple components.   Your thermostat, radiator, water pump, engine coolant passages, heater core and the hoses connecting them all make up your vehicle’s cooling system.  The only moving components are your water pump and the thermostat.  If your thermostat sticks shut it can cause your vehicle to overheat.  Also, if your water pump fails it won’t move the coolant through your engine causing it to overheat as well.  These two components failing are unlikely due to normal wear but can break under extreme conditions.

The other components in your engine’s cooling system will fail due to rupturing or leaking.  Most often, it turns out to be a leak that causes your engine to overheat.  If enough coolant leaks out of your cooling system, then there isn’t enough coolant to remove all of your engine’s waste heat.  Finding the source of your cooling leak can be a complicated process due to the location of the cooling system components and the fact that coolant doesn’t leave a residue like leaking oil does.

Sealing a cooling system leak is now a much simpler process with BlueDevil Heat Gasket Sealer.  BlueDevil Head Gasket Sealer is designed to seal the cooling system leak in your vehicle, specifically those from your engine’s cooling passages sealed by your head gasket.  BlueDevil Head Gasket Sealer is BlueDevil’s most powerful cooling system sealing product and can stop the leaks in your vehicle’s cooling system guaranteed!

BlueDevil Head Gasket Sealer

For more information about BlueDevil Head Gasket Sealer, how to use it, and to purchase it online, click here.

You can also purchase BlueDevil Head Gasket Sealer from any of our partnering local auto parts stores:

  • AutoZone
  • Advance Auto Parts
  • Bennett Auto Supply
  • CarQuest Auto parts
  • NAPA Auto Parts
  • O’Reilly Auto Parts
  • Pep Boys
  • Fast Track
  • Bumper to Bumper Auto Parts Specialists
  • S&E Quick Lube Distributer
  • DYK Automotive

Pictures provided by:

Broken Car – by Michael Pereckas “Stuck Car” in “Ski” -Licesenced under Creative Commons Share Alike 3.0 Original Link

24 responses to “Why Is My Car Overheating in the Winter?

  1. If the head gasket sealer will seal the coolant system, will i have heat for the winter??? How long is this stuff good for??? Will it get me through the winter without having to replace the heads or engine?????

    1. Kay-

      Yes, once the cooling system has been sealed you will then get full heat coming through your vents. BlueDevil is a permanent seal, you will not have to apply the product more than one time. We have had customers contact us back after 2 – 3 years of using the product and the seal is still holding.


      1. My dodge Durango sport stared running hot and the smoke started coming through the vents and my heat is going in and out I could barely defrost my windows. What can I do

        1. Yanda-

          Thank you for asking about your Dodge Durango Sport. Based on your description, it is possible that you are experiencing a heater core leak. Have you noticed a loss of water/coolant? You may want to take the vehicle in to a certified ASE mechanic for a proper diagnosis. If it turns out you are losing water, we recommend using the BlueDevil Head Gasket Sealer (http://store.gobdp.com/head-gasket-sealer-38386/).

          Thank you!


  2. I applied your Head Gasket Sealant about 9 months ago and it worked incredibly. Now, I have a small leak in my coolant bypass pipe so wonder if you would recommend another round or should I try to Radiator Block sealant?


    1. Joe-

      First of all, we are very glad you have had success with the BlueDevil in the past. For your new leak we recommend adding a bottle of the BlueDevil Radiator & Block Sealer. It should have no problem sealing the leak from your bypass pipe.



  3. I just put the Blue Devil pour n go into my car n when I ran it idle for 50 minutes my car was over heating!? Why?

    1. Elizabeth-

      If the vehicle overheats during the 50 minute idle then that may be an indication that the leak is a little bit too large for what BlueDevil is intended to fix. Feel free to contact us at 888-863-0426 to initiate the warranty process.

      Thank You!


  4. Will your radiator flush work on a blockage that is in the hoses or if you aren’t sure where the blockage is like in the water jackets of the engine block?

    1. Lisa-

      It really depends on the nature of the blockage. If it is due to old jellied antifreeze or buildup from normal wear and tear then there is a very good chance that BlueDevil Radiator Flush will free it up and get the cooling system running properly and efficiently.

      Thank you!


  5. I have been having issues with overheating especially when it’s cold it goes up higher. Thermostat, and water pump were replaced. Nothing wrong with the radiator. Thinking it’s the sensor. Recently my heat stopped working. What do you recommend?

    1. Casandra,

      Thanks for your question about your vehicle overheating. Our first recommendation would be to check your coolant level to make sure it’s not low. An extremely low coolant level could cause both overheating and your heat to stop working due to a lack of coolant flowing through your heater core. If you find a low coolant level, use the appropriate BlueDevil stop leak agent to seal the leak and then top off your cooling system. If your vehicle is full of coolant and your heat still isn’t working, you could have a clogged heater core which would cause the same issues. Try checking the temperatures of the inlet and outlet hoses of your heater core. If there is a large temperature differential, larger than 20 degrees, you might have a clog there.

      Thanks again for your question!
      -BD Auto Pro

  6. So out of the blue my 2000 Durango 360 decides to overheat. I’ve had problems in the past where I’ve changed radiator,thermostat and water pump. All three are brand new. Now for the kicker. It just started the last two days. Temps are -30 with windchill. Heater does not work well and hasn’t for 3 years now. No smoke from the heads either. Could it still be headgasket? Heater core not leaking, no water inside vehicle. Ideas?
    Oh and no clogs in heater core and plenty of coolant.

    1. Steve-

      Thank you for asking about your Dodge Durango. Based on your description, it is possible you have an issue with flow. Being that the radiator, thermostat and water pump were all just replaced, the system may have an air pocket trapped, which is restricting water/coolant circulation and causing the vehicle to overheat. You can try bleeding the system to get rid of potential air pockets to see if this corrects the issue. If not, it may also be possible that you are getting combustion/exhaust gases pumping back into the cooling system.  You can use a “Block Dye Tester” to confirm whether or not that is the case.
      BlueDevil Head Gasket Sealer will still work if your vehicle is getting combustion/exhaust gases blowing into the cooling system and creating pressure.  To give yourself the best overall chance of BlueDevil working successfully, in addition to the directions, you should remove the spark plug from the cylinder with the leak; this will be the spark plug from the cylinder with the low compression reading.  If you are not sure which one that is, you may pull all of the spark plugs and will notice one will have a white-crystal-like substance on it and/or may look dirty; this is the plug you should pull.  Leave that plug out for the 50 minute idle in order to relieve the pressure from building up and thus allowing the product to seal properly.  Be sure to follow the guidelines for the proper amount to use based on the size of your cooling system.

      Thank you!


  7. On today my temp gauge showed my expedition was running hot but the temperature outside was 21 degrees. My heater core was giving me problems so it was bypassed about a month ago. I drove about 5 mins and noticed the temp gauge on hot. Could this be fixed using one of your products once the engine thaws or am I looking at a bigger issue?

    1. Latasha-

      Please contact our technical support line at 888-863-0426 so that we can get a better understanding of the vehicle’s condition and be able to make any appropriate recommendations.

      Thank you!


  8. My venture mini van temp gauge reads past hot. It starts out at the half way mark or just past when first starting van. But ive had it checked out several times they say its not hot cause the hoses arent not to hot to touch. Ive changed out the temp sensor already. What could be causeing this?

    1. Elnora-

      Thank you for asking about your Chevy Venture. Just to confirm, are you saying that from a cold start, the temperature gauge starts at the half way mark? Please contact our technical support line at 888-863-0426 so that we can get a better understanding of the vehicle’s condition and be able to make any appropriate recommendations.

      Thank you!


  9. My Getz Shows the over heating sign when the car is cold I changed the radiator water pump thermostart and fan switch and I did the engine overall.What can be the problem

    1. Lesego-

      Please contact our technical support line at 888-863-0426 so that we can get a better understanding of what kind of vehicle it is and the vehicle’s condition, and be able to make any appropriate recommendations.

      Thank you!


    1. Shianne,

      Turning the heat on removes heat from your coolant by blowing air through your heater core into the cabin of your vehicle. Your car is most likely overheating due to a low coolant level or a problem with your engine’s cooling fans. There are other problems that may cause overheating, but they are much rarer. We would recommend checking your vehicle’s coolant level in accordance with the car’s owner’s manual and checking the cooling fans for proper operation when your engine is warmed up and idling.

      Thanks again for your question!
      -BD Auto Pro

  10. My 99 cutlass. Gets hot and no heat but if I hold the idle at 2000 it acts like it opens something up and temp gauge goes down and I get heat but then when I take my fit off I lose it. After a couple times of this it seems to b OK temp and I have heat but then when I turn it off im right back to the beginning. I was told maybe the intake gasket but I’m not sure. Would this product help my issue

    1. Bobbi-

      Thank you for asking about your Oldsmobile Cutlass. Are you noticing a loss of water/coolant? Please contact our technical support line at 888-863-0426 so that we can get a little better understanding of the vehicle’s condition and be able to make any appropriate recommendations.

      Thank you!


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