Winter’s frigid temperatures often take us by surprise. One morning you walk outside, ready to head off to work, and stop dead in your tracks. Overnight, the thermometer has plummeted to a teeth-chattering low. You ponder with dread, “It’s so cold out…will my car even start?” If you’ve found yourself in this bone-chilling predicament, fret not. This comprehensive guide will equip you with everything you need to know about getting your wheels cranked when the mercury plunges.
So, what is the lowest temperature most cars can start at? With a sturdy battery and proper oil, the majority of modern vehicles will start okay in temperatures down to 0°F/-18°C or a smidge below. Well-maintained cars with robust batteries can fire up their engines at -10°F/-23°C or lower. And if you have a high-performance battery installed, starting is possible at frigid temps like -30°F/-34°C. Once the mercury dips under -40°F/-40°C, however, it becomes tricky for all but the heartiest of vehicles to turnover their engines.
Prep your car properly and you’ll be ready to take on Old Man Winter’s worst. Read on to learn all about cold cranking amps, oil viscosity, gas tank levels, battery blankets, and other essential tips that’ll ensure you stay mobile when the thermometer plunges. Let’s defrost this topic and get rolling.
Table of Contents
What Factors Allow Cars to Start in Cold Weather?
Okay, before we dive into the nitty gritty details, let’s quickly overview the key factors that enable cars to start in frosty conditions:
- Battery power – The battery must have ample cranking power to turn over the starter motor and get the engine spinning. Cold Cranking Amps (CCA) measure a battery’s starting capacity in chilly weather. More on that next.
- Oil viscosity – Oil thickens in cold temperatures and resists flowing freely. Lower viscosity winter oils make starting easier when it’s cold out.
- Strong ignition and fuel systems – Weak spark plugs or coils, clogged fuel injectors, and other ignition issues make starting difficult.
- Gas tank level – At least a half tank of gas is recommended so the fuel pump doesn’t suck in air and stall.
- Garage parking – Storing your car in a garage protects the battery and interior components from extreme cold.
Okay, with the basics covered, let’s explore each of these key factors more in depth so you understand exactly why they’re important and how they allow your engine to turn over on even the most bone-chilling winter morning.
What are Cold Cranking Amps (CCA)?
Perhaps the most crucial factor in cold weather starting is having a battery with ample cold cranking amps (CCA). CCA is a measurement used in the automotive battery industry that indicates how much electrical power a battery can deliver to the starter motor at 0°F/-18°C.
The starter motor draws a massive electric load in order to spin a cold, thickened engine fast enough to ignite the spark plugs and initiate combustion. We’re talking several hundred amps required for 4-6 seconds of cranking in frigid conditions before the engine finally roars to life. That’s why you can often see your headlights and interior electronics dim when trying to start in extreme cold. The starter motor is gobbling up all available juice from the battery.
Therefore, the higher a battery’s cold cranking amp rating, the more “oomph” it can supply to get the engine cranking and started in wintry temperatures. Car manufacturers include a recommended CCA rating in the owner’s manual for the climate you live in. For example:
- For moderate climates, a CCA of 200-300 amps may suffice.
- Colder regions may recommend 500-600 CCA.
- Extreme cold locations like Alaska often call for a minimum of 800+ CCA.
Checking your battery’s CCA rating is important. Installing a battery with insufficient starting power can leave you stranded when the mercury plummets. Opt for the highest CCA-rated battery readily available that meets or exceeds your carmaker’s recommendation.
And if your battery is more than 3 years old, its starting capacity has likely diminished. Have it tested at your local auto parts shop and replace it proactively before winter sets in. Don’t get caught off guard by a weak battery when it’s 10 below zero outside!
How Oil Viscosity Impacts Cold Starting?
Another essential cold-starting factor is having engine oil of the proper viscosity, or thickness. As temperatures drop, oil inevitably thickens and flows more sluggishly – like molasses on a cold day. This increased viscosity makes it more difficult for the starter motor to spin and crank the engine.
That’s why using specially formulated winter or cold-flow engine oils is critical. These oils contain additive packages with higher proportions of lower viscosity base oils that remain fluid and flow freely even in sub-zero temperatures.
For example, typical 10W-30 oil used in summer may thicken up significantly below 32°F/0°C. But switching to 5W-30 or 0W-20 winter oil provides much lower viscosity at low temps so the oil pumps easily and allows the starter motor to spin the engine faster. Just be sure to switch back to the manufacturer’s recommended viscosity when temperatures warm up again in spring.
Many newer cars even have an automatic “oil warm up” cycle that briefly runs coolant through the oil system on ignition to warm and thin the oil prior to starting in cold weather. It’s an ingenious system that improves cold start performance. So if your engine seems to run briefly before actually cranking over, no need to fret. The car is just ensuring the oil flows freely before engaging the starter motor.
So invest in the best cold-flow engine oil to give yourself the best shot at firing up the engine when temps take a tumble. Your owner’s manual will indicate the proper oil viscosity grade for winter driving conditions in your area.
Does Gas Tank Level Matter for Starting?
Here’s a quick but important tip when attempting to start in biting cold temperatures – keep your gas tank at least half full or preferably nearly full. This prevents the fuel pump from sucking in air through the evaporation of gas, which can stall the engine and make cold starting nearly impossible.
See, frigid winter air temperatures combined with warm underground fuel tanks cause gasoline to evaporate and turn gaseous. As the fuel pump draws from the tank, it can end up pulling in vapor if the tank level is too low, causing erratic performance or stalling. The miniscule gas bubbles act like tiny air pockets that interrupt the fuel stream and prevent the injectors from pressurizing properly.
Not only does this starve the engine of robust fuel spray, it also allows unburnt fuel vapors to enter the manifold, diluting incoming air and robbing power. It’s a double whammy that can stop an engine dead in its tracks.
The fix is simple – just keep your tank well topped off during the winter months. This gives a nice liquid cushion for the pump inlet to avoid sucking vapors from the bottom of the tank. Once temperatures warm up in spring, evaporation decreases and lower fuel levels become less problematic. But heading into a polar vortex or Siberian cold snap? Keep that tank filled up!
Does Parking in a Garage Help?
When old Jack Frost is nipping at your nose, another smart preparatory move is to park your vehicle in a garage if at all possible. This shelters your car from the harshest overnight and early morning cold snaps that can sap battery power and cause components under the hood to contract dangerously.
While modern engines and lubricants are engineered to withstand even extreme subzero temperatures while running, severe cold has a greater impact on parked vehicles. Prolonged exposure allows the battery electrolyte to crystallize, reducing available cranking amps. The viscosity of engine oil and transmission fluid also increase dramatically as overnight lows plummet. This makes it much harder for the starter motor to churn the engine over. Metal engine parts can even contract slightly and lead to harder starting.
By contrast, parking indoors reduces thermal shock by keeping your vehicle closer to the ambient garage temperature overnight. The warm enclosure provides a buffer against frigid overnight air, allowing a smoother cold start come morning. Your initial crank will sound quicker and stronger.
If indoor parking isn’t an option, even covering your car with a thick insulated blanket can provide some cold protection. Just be sure to remove it completely before driving to avoid the cloth getting caught in moving components. And leaving your car idling to warm up is wasteful of fuel. A better tactic is to ease gently down the road until reaching normal operating temperature.
Do Battery Warmers and Block Heaters Help?
For folks dealing with regular subzero temperatures, investing in additional battery and engine preheating systems can make a huge difference in cold weather starting capability. Two popular options are:
Battery blankets/warmers – These are microfiber insulating sleeves that wrap around the battery. Some have heating elements that raise battery temperature to improve cranking amperage. Just be careful not to overheat the battery.
Engine block heaters – These electric heating elements warm the engine coolant overnight to reduce viscosity. Somecirculate warm coolant directly through the oil gallery. They plug into a regular wall outlet. Installing an interior timer allows preheating the engine a couple hours before your morning departure. Even periodic use improves cold starting performance.
While not mandatory, having one or both of these systems offers inexpensive insurance against getting stuck on the coldest days. They take the bite out of extreme winter battery and engine conditions. Just remember to unplug the block heater cord before driving away. And remove battery blankets so they don’t catch fire or chafe and short out. A little preparation goes a long way!
Reviewing Other Cold Weather Startup Tips
To boost your battery’s cranking potential and make the most of your engine’s cold-weather performance, it helps to follow some additional winter driving best practices:
- Check fluid levels – Top off antifreeze, brake fluid, transmission fluid, and windshield wipers to rated levels. Use winter grade washer fluid with antifreeze.
- Inspect ignition system – Weak spark plugs, bad coils, and faulty ignition modules can worsen hard starting. Replace worn components.
- Change fuel filter – Clogged filters prevent robust fuel delivery and pressure needed for winter starts.
- Use winter tires – They provide much better traction and mobility in icy, snowy conditions. Don’t get stuck behind the wheel spinning.
- Pack an emergency kit – Include a flashlight, jumper cables, traction mats, blankets, non-perishable snacks, medications, flares, and other cold weather gear.
- Check tire pressures – Lower pressure improves traction on snow and ice. Inflate to guidelines for cold conditions.
- Clear ice – Make sure wiper blades aren’t frozen to windshield and all lights are free of ice and snow buildup before driving.
For a full winter prep checklist, consult your owner’s manual maintenance schedule. Advance preparation helps avoid being caught off guard by Old Man Winter. Stay on top of basic maintenance and your ride will take everything the cold weather season throws at it in stride.
The Bottom Line
So when temperatures really bottom out, what’s the lowest temperature the average car can still start at?
Let’s recap the key benchmarks:
- With a decent battery and proper viscosity oil, most modern cars start okay in the range of 0°F/-18°C or perhaps slightly below. Owners report they can usually get their vehicles going to at least -10°F/-23°C if well maintained.
- Upgrading to a high performance battery with 800+ cold cranking amps enables starting around -20°F/-29°C for some vehicles.
- Extreme cold weather batteries with 1000+ amps may allow starts at up to -30°F/-34°C.
- Once ambient air temperatures plummet below -40°F/-40°C, it becomes very difficult for all but the most cold-hearty vehicles to turnover and start. Even diesel engines with grid heaters usually fail below -40°.
Of course, the exact lowest starting temperature depends greatly on the make and model of vehicle, engine size, battery condition, oil viscosity, and other factors like gas tank level and preheating capacity.
A big eight cylinder truck engine is typically easier to start in bitter cold than a small four cylinder economy car. And newer cars with advanced glow plugs and piston rod heaters fare better than older, carbureted models without cold start aids.
The bottom line is that with some preparation and robust equipment, you can keep your ride ready to roll even when the temps drop down to -30° or lower on the coldest winter days. That gives you confidence to go about your business and not worry whether your engine will catch and fire up as needed. Just follow the battery, oil, and winter prep tips provided above and you’ll drive through the deep freeze without a hitch.
Stay warm and safe travels! Let me know if you have any other cold weather driving questions.