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Car Won’t Start in the Cold? Check Out these Troubleshooting Tips

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If your car won't start in the cold, the best solution combines proper maintenance and options to make a cold start easier on your vehicle.

In northern Wisconsin, cold winter weather is a fact of life. My 2007 Saturn Ion starts in weather as cold as -25°F actual temp without fail, without any special treatment. (But not everyone is so lucky.)

We have a fleet of trucks at work (both diesel and gas) that run in all kinds of weather. I’m drawing on my experience working with them, and from full time mechanics that help troubleshoot when we need them.

frost covered car that won't start in the cold weather

If Your Car Won't Start in Cold Weather, First Check for Proper Maintenance

  1. Make sure you have the right oil. Most cars now recommend 5W-20 for year round use, or synthetic such as Mobil One.
  2. Have your battery checked. In our area, most auto parts stores will do this testing for free. Car batteries can fail after 3 or 4 years, a quick test will tell you if you have a weak battery and it needs to be replaced. You can also test your alternator to see if it is charging the battery properly.
  3. Get service if it is needed. If you have a check engine light on but don’t notice any change in performance, there may still be a problem with your ignition system that will get worse in cold weather. Electronic ignition on modern vehicles is more dependable than ever, but coil packs do fail. There may also be other problems that only a mechanic with the right diagnostic equipment can troubleshoot.

Side note – when you take your car to a service station for oil change, don’t let them fill your washer fluid reservoir.

They typically use a low grade washer fluid that will freeze when the cold comes. Once that happens you will be at nature’s mercy until it warms enough to pump it out. Get cold weather windshield washer fluid.

When Winter Hits – Steps to Improve Cold Weather Starts

There are several things you can install to warm the key parts to make cold starts easier. It's better to get the installation done before cold weather hits, but options like an engine blanket can be easily added during cold weather.

Note: Cars and trucks built after 1990 have fuel injection. The recommended starting sequence should be in your owner’s manual.

Use a Battery Blanket

A battery blanket is a straightforward way to avoid some cold start issues.

Cold weather slows the chemical reaction inside your battery that makes the electricity to turn the starter, and can rob you of 30% of your cold cranking power.

A battery blanket needs to be active for about an hour to do its job and warm the battery to the core. Get a battery blanket on Amazon.

Try an Engine Block Heater

Engine block heaters come in 3 different types:

You can install these yourself if you do some research and make sure you have the right style for your particular application. (I would get a mechanic for the frost plug style.)

When doing research to write this post, I found that Amazon had a built in guide to help you find the right one for your engine. Just type in the make, model and year to find the right fit.

No matter what style of engine block heater you have, an hour should be enough to warm the engine once it is plugged in. There are timers you can purchase that can be set for an hour before you need to start your car that will save you money.

Because they create heat, all of these heaters draw quite a bit of current and should be plugged into a 20amp breaker that does not have other appliances.

Start Your Car the Right Way

The way you start your car can improve your chances of a cold start.

  1. First, turn off the headlights and blower for the heater.
  2. Next, turn the key to the on position and wait until the dash lights quit flashing. This allows the fuel pump to pump additional fuel in for the cold start.
  3. Finally, turn the ignition key and crank the engine for up to 10 seconds. If it fails to start, wait 30 seconds and try again. Don't try this more than 3 or 4 times. At that point you likely have a dead battery and you will need to find a way to recharge it.

To jump start your car or other vehicle – pay attention to the color codes on the jumper cables and battery terminals. Make sure the red goes to the positive post and the black negative ground is attached to the engine block. 

Allow several minutes for the battery to recharge (with the jumper car running) before you try to start your vehicle.

It takes 12 minutes or more for a working alternator to recharge a cold battery, so don't shut off the car after it is jumped until it has been driven an adequate amount of time.

Cold Weather Start with Diesel Engines

Diesel engines have glow plugs with an indicator light that tells you when they have warmed enough to attempt a start. Diesel engines start harder because of higher compression and a higher flash point for the fuel.

For temps below zero, we always plug our trucks in to warm the engine block.

HEET™ Fuel Additive – Yes or No?

Gasoline Engines

Modern fuel contains an ethanol mix of 10% or more, so you shouldn't need to treat your fuel with “HEET™” gas line antifreeze. (Assuming you use your car regularly.)

Diesel Engines

If you have a diesel engine, you should use a fuel conditioner at the recommended rate. It is also beneficial to keep your tank past half full to minimize condensation in your fuel tank. (This is a good tip for both gasoline and diesel engines.)

Water lowers the octane of the fuel and causes poor performance. Additives such as Sea Foam motor treatment can boost octane and remove water for better overall performance.

My Car Still Won't Start – Now What?

This is an introduction to cold weather car starts, not a complete guide. Always refer to your vehicle's owner’s manual and back that up with the advice of a reputable mechanic.

Modern auto mobiles often stay on the road for 200,000 miles and are complex in design. Sometimes even the professions have problems troubleshooting issues.

car on cold morning that won't start

Don't Forget to Check Your Tires

Don't forget to check the air pressure in you tires.

Rich says, “I started my Ford Edge today and took it for a ride to just drive it and charge the battery. It was pulling to the driver's side so I checked the air pressure and it was less then 10#, when it should have 35#.

I checked all 4 and the MOST I had in any tire was only 25#. I know cold weather drops the air pressure because I always have to inflate my wheel barrow. This is something we don't want to do when it is cold, but really should.”

You may also find our other Common Sense Preparedness posts useful, including:

Richard Poplawski

This post is by Laurie Neverman's brother, Richard Poplawski. Since his service in the Marines, Rich has been a mechanic, fabricator and “fix just about anything” guy for over 20 years. He lives in northwest Wisconsin in the farmhouse that was owned by his grandparents, and maintains a large orchard and perennial plantings, as well as a vegetable garden. He loves spending time with his grandkids, introducing them to gardening or getting in some fishing with “Papa Rich”.

His posts on the site include:

Originally published in 2016, updated in 2018.

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17 Comments

  1. This is such a good article, with lots of good advice. I love your tip about using a heated blanket for your battery! I didn’t know that was even a thing, but I’ll definitely have a look into it now! I recently had an experience where my car broke down and wouldn’t start! I was stuck for two hours waiting to be rescued (which I know doesn’t sound like a long time – but when you haven’t eaten all day and only have 2 polos in your bag, it can feel like an age!) But I’ve learnt from my mistakes and am now desperately trying to teach myself more about cars and how to handle breakdowns! I actually read an article recently (this is the link) where it mentioned that sometimes the wheel can lock? Can that be an affect of the cold? Sorry if that’s a really dumb question to ask, but I am such a rookie when it comes to things like this – so any help you could offer would be amazing!

  2. My 2006 Ford 500 will not start in cool weather (60f or below). I have had the throttle and ignition replaced along with a new key. My mechanic has utilized the diagnostic equipment and cannot find the cause. Also has checked the fuel pump which is fine. The car has 140000 miles on it. Any ideas what may be wrong?

    1. It’s pretty much impossible to diagnose mechanical issues long distance. (No psychic mechanics in house, unfortunately.) You might try a different mechanic (Ford garage, for instance, even though they’re pricier), or a different fuel blend (ethanol free). Maybe there’s something wrong with the vehicle computer and it’s telling the injector to shoot in less fuel when the temp drops?

      There is one recall on that vehicle, and it’s related to the fuel system – https://www.carcomplaints.com/Ford/Five_Hundred/2006/recalls/

  3. Recently replace my old battery with an OEM battery. The car would not turn on when its really cold out and only will turn on when I get a jump or use a battery starter. What can be causing this?

  4. Just one question: RE:
    HEET™ Fuel Additive – Yes or No?
    Modern fuel contains an ethanol mix of 10% or more, so you shouldn’t need to treat your fuel with “HEET™” gas line anti freeze. (Assuming you use your car regularly.) If you have a diesel engine, you should use a fuel conditioner at the recommended rate. It is also beneficial to keep your tank past half full to minimize condensation in your fuel tank. Water lowers the octane of the fuel and causes poor performance. Additives such as Sea Foam motor treatment can boost octane and remove water for better overall performance

    It is a bit confusing as you refer to a diesel motor in the paragraph. Is the product you mention for diesel, or gasoline engines?
    Thanks for the great information!

    1. Sorry about any confusion, Carol. I’m going to divide that into two different paragraphs for clarification. With the ethanol in gasoline, there shouldn’t be a need for additives in a gasoline vehicle that’s used regularly. Because diesel tends to thicken at low temps and doesn’t contain additives such as ethanol by default, in cold weather it is helpful to use a fuel conditioner in diesel vehicles.

  5. Starter clicks lights turn on and heater turns on but engine won’t turn over it’s-30 outside and I really need to start my car any ideas I have no blanket or garage to warm it up. I try jist recently and it turned 9ver once shpuld i keep.trying or should I leave it alone?

    1. It’s hard to say what’s best without being able to see/hear the car. Turn off all non-essentials before attempting to start the vehicle. If it’s catching, i.e., starting to turn over and you can get it run, then keeping it running and driving it around will help charge the battery. (If you get it started, let it warm up and drive slowly initially.) If it’s “mostly dead” with little response, your odds of draining the battery before getting it started are high. In case of emergency, you have nothing to lose by trying. Call for 911 for help if you are stranded.

  6. Laurie, I thought you might enjoy hearing how I learned to start a car on the reservation, at a home where there was no electricity and the temp was way below zero.

    The people save their clean, empty gallon jugs all year. When the car won’t start, first you fill all your jugs with the hottest tap water you can get. Then you take the jugs outside and tuck them in all around the engine, wherever there is room. Next, you take a warm blanket and lay it over the engine and all the jugs. You shut the hood and go back inside. In about an hour, the car should start if nothing is mechanically wrong. I saw this work many times.

    Thanks to you and Rich for this useful winter info!

  7. Bought a 2004 Acura TSX about 8 months ago. Got 190 000 kms on it. Noticed that even in warm weather it takes quite a bit of cranking (ie 10 cranks) before it fires to life with gusto. When cold weather hits, it often starts cranking with a lot of life (that would easily start most other cars) and gets me hopeful it will start but after 15 seconds gradually battery dies and stops cranking (understandably) I’m going to be changing the spark plugs soon to see if that is the problem but so far I haven’t had any problems with misfiring or losing power so I don’t think that’s the problem. At the moment the only heater I have is an oil pan adhesive heater.
    Would appreciate some advice on how to make the engine ‘catch on’ better!

    1. Rich says, “Odds are it’s a fuel problem, either filter is dirty or pump is weak. If it turns over and runs fine once it starts the computer might not be sending enough gas when it’s cold.”

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