Car Overheating in Winter
Roadway Tips

4 Possible Reasons Why Your Car is Overheating in Winter

Ah, beautiful winter!  Another crisp ten below zero-day, what could be better?  You’ve been putting off getting your car fixed because it’s been so cold.  It was running a little bit hot, but it’s winter now.  I shouldn’t have to worry about my car overheating.

What a shocker it will be for you when you get down the road and steam starts billowing out from under your hood.  Why is my car overheating in the winter?!?  How is this possible?  

Your car overheating has nothing to do with the temperature outside, but rather, something has gone terribly wrong with your car’s cooling system. From coolant fluid to a thermostat, even a mouse (?); could all be possible causes for a coolant system failure.

Without a properly functioning cooling system, it will not take long for your car to overheat.  So let’s take a look at a few of the components of your car’s cooling system and find out what’s wrong.

Possible Causes Why Your Car is Overheating in Winter

Low Coolant Levels

Let’s start with the easiest solution.  Your vehicle has low levels or is using old radiator fluid.  If there are insufficient levels of coolant in your system, it will not cool your engine down properly.  Even with bitterly cold temperatures outside your car’s engine heats up to several hundred degrees; it won’t take long to overheat.

This problem you can easily remedy yourself.  Check the coolant reservoir tank. If you don’t see any coolant in there, voila, you have discovered the problem.  You can get some coolant from Advanced Auto Parts here or from Amazon here.  Or you can go down the street to the Dollar Store and get some.  

Fill up your reservoir tank and see what happens.  You should be good to go.

Everything else that could be a problem will most likely require some mechanical work. 

Stuck Thermostat 

While making sure you have sufficient radiator fluid is the easiest solution; a more likely culprit is a bad thermostat.  Much like the thermostat in your house regulates the temperature indoors; a car’s thermostat regulates the temperature of the engine.

If the thermostat goes bad or gets stuck, it will not allow the radiator fluid to flow through the engine.  Obviously, when this happens the engine doesn’t cool and it begins to overheat.  

What Are the Signs of a Bad Car Thermostat?

According to autoblog.com, there are three telltale signs of a bad thermostat.  If you see any of these signs you may want to take your car for a checkup.  

  1. Temperature gauge reading very high (overheating engine)
  2. Wildly fluctuating engine temperature
  3. Signs of coolant leaks around the area of the thermostat or on the ground

So keep an eye on that temperature gauge.  It’s more than just a pretty decoration on your dashboard.  It actually has some useful information. 

Possible Causes Why Your Car is Overheating in Winter-Part Deux

To Much Air 

The good people at Napa say another reason your car could be overheating is a not completely sealed cooling system.  As in, the cold outside air is getting into your cooling system.  This is actually fascinating, because as they explained it; the cold outside air expands when it comes in contact with the warm environment inside the engine.  When the air expands like this, it actually chokes the amount of coolant moving through the engine.  Which leads to an overheating engine.

Air will usually leak in through a dry-rotted radiator hose.  Depending on your vehicle these hoses can be difficult to replace yourself.  Also, the radiator will need to be flushed and any air in the system bled out.  It may be best to seek out an experienced mechanic to do this for you.

Blocked Exhaust System

The last reason may be the most interesting of all because it is not a mechanical problem per se.  A compromised exhaust system could also be the reason for your car overheating in winter.  

Your car’s engine creates a lot of heat and for it to run efficiently it needs to expel that heat.  The engine does this in a number of ways, but the main method by means of the exhaust system.  Ever wonder why your muffler is so hot?

Well, just like you, rodents, mainly mice, don’t like to be cold in the winter.  They also need a place to shelter.  Your car’s exhaust system is the perfect home. 

Any encumbrance to the exhaust being expelled may cause an overheating engine.  This could include a damaged tailpipe or muffler.  If the flow of exhaust is compromised your car engine may overheat.

What To Do If Your Car Begins to Overheat

I covered this topic over here, but to sum it up there are three primary steps you can take.  And in winter…actually two steps.

  1. Turn off your air conditioner.  Since it’s winter, this is probably already done, unless you’re a sicko. 
  2. Turn on the heater.  Again probably already done, but turning the heater on full blast will help dispel some engine heat.
  3. Find a safe place to pull over.

JUST AS A WARNING DO NOT TRY TO REMOVE THE RADIATOR CAP WHILE THE ENGINE IS HOT.  THERE IS SUPER-HEATED FLUID AND PRESSURE BEHIND THAT CAP; IF YOU REMOVE IT, YOU WILL GET BURNED.

There is not much to do now.  You will need to wait about 30 minutes until your engine is cooled down enough.  At that time, make a plan on how you can get to a safe place. 

Final Thoughts…

Winter is the last time of year that you would think of your car overheating.  But just because it’s cold outside doesn’t mean it’s cold under your hood. 

General maintenance of your car should prevent this from ever happening to you.  Check your fluids regularly.  A quick inspection of the hoses will show if they are beginning to deteriorate.  The same thing goes for checking for critters in your exhaust.  

Be aware of your temperature gauge, hopefully, this will give you a little warning before something seriously goes wrong.

There is the possibility that something could be grossly wrong with your cooling system.  These items listed are fairly easy to check for and get fixed.  Just be mindful of your car, if something seems wrong, take it to the mechanic and have it checked out.

It’s easier to do that than be stuck on the side of the road in the bitter cold.  Stay safe people.

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