Car Won't Start in the Cold? Boost or Tow

It’s dark, it’s -30°C or colder, and you’re already late. You turn the key or press the button, and instead of the engine catching you get a slow, tired groan. Or a click. Or nothing at all.

It’s a familiar story every Edmonton winter. The good news is that a dead battery is often a quick fix. The bad news is that sometimes it isn’t the battery at all. This guide helps you tell the difference, so you know whether to ask for a jump start (in Alberta we call it a boost) or a tow.

Why cold is hard on batteries

A car battery makes power through a chemical reaction, and cold slows that reaction down. On a bitter morning, the battery simply can’t deliver as much power as it can on a mild day.

At the same time, the engine is harder to turn over. Oil thickens in the cold, so the starter needs more power to crank the engine. Less power available, more power needed. That’s why a battery that seemed fine in October can let you down in January.

Older batteries feel this most. A battery that’s been weakening for a while may get through the autumn and then give up on the first truly cold morning.

It just clicks

A rapid clicking when you try to start often means there’s not enough power to turn the starter. That usually points to a weak or dead battery, and a battery boost has a good chance of getting you going.

The lights come on but it won’t start

A slow, laboured crank. The engine turns over, but sluggishly, as if it’s struggling. That usually points to a weak battery.
Dim or flickering lights. Headlights or dash lights that are weaker than normal point the same way.

If these sound familiar, a boost has a good chance of getting you going.

No click, no lights

Nothing at all. No lights, no sounds, no response usually means the battery is dead.
You left something on. Headlights, an interior light or an accessory left on overnight can drain even a healthy battery.
The battery looks damaged. A cracked, bulging or leaking battery should not be boosted.

The battery seems fine but it still won’t start

Some symptoms suggest the problem is more than the battery:

It cranks normally but won’t start. If the engine turns over at normal speed but never fires, the battery is probably fine. The problem may be fuel, ignition or something else.
It started after a boost, then died again soon after. That can point to a charging problem rather than a battery that just needed topping up.
Warning lights stay on after it starts. A battery or charging warning light that stays on while you’re driving is worth taking seriously.
Strange smells, smoke or noises. A burning smell, smoke, or grinding or squealing noises are signs to stop and get help, not to keep trying.

If you’re seeing these, you’ll probably need a tow to a mechanic who can find the real cause.

When a boost works

A boost works when the battery is drained but otherwise healthy, and the rest of the starting and charging system is doing its job. It’s the right call when:

you left something on and drained the battery
the vehicle sat out in the cold, especially for a few days
the battery is weak but not damaged, and the vehicle starts promptly once boosted

After a boost, don’t switch the engine off straight away. Drive for a while so the battery can recharge. Then have the battery and charging system tested. A battery that needed a boost once may need one again on the next cold morning.

When you need a tow

You’ll likely need a tow when:

the vehicle won’t start even with a boost
it starts but dies again soon after
there are signs of a bigger fault, like smoke, smells, grinding or warning lights
the battery is visibly damaged
the vehicle isn’t safe to drive for any other reason

If your vehicle is AWD or 4x4, mention it when you call. Those are best moved on a flatbed, with all four wheels off the ground.

Boosting it yourself: be careful

If you have cables and a second vehicle, you can boost a battery yourself. Do it carefully.

Read your owner’s manual first. Some vehicles have specific boost points or instructions.
Check the battery. Don’t boost a battery that’s cracked, swollen, leaking or frozen.
Connect the cables in the right order as shown in the manual, and keep the clamps from touching each other.
Keep sparks and flames away from the battery.
Don’t keep cranking. If the engine doesn’t catch after a few short tries, stop and call for help.

If you’re unsure about any step, or it’s too cold to stand outside fiddling with cables, call for a boost instead.

Cold-weather battery tips

A little preparation goes a long way.

Have the battery tested before winter. Many shops can check it quickly. It’s better to find out in October than in a parking lot in January.
Plug in your block heater on cold nights, if your vehicle has one. A warmer engine is easier to start.
Park inside if you can. A garage, even an unheated one, keeps the vehicle out of the wind.
Switch things off before you shut the engine down. Lights, heater fan, heated seats and anything plugged in.
Drive long enough to recharge. Lots of short trips in the cold may not give the battery time to recover.
Keep your tank from running low. It’s one less thing to worry about on a cold morning, and an empty tank won’t start any better than a dead battery. If you do run dry, we offer fuel delivery.

What to tell us when you call

To help us figure out whether you need a boost or a tow, tell us:

where the vehicle is
what happens when you try to start it: a click, a slow crank, a normal crank, or nothing
whether anything was left on
whether it has been boosted recently
what you drive

We’ll give you the price before we start. If the boost works, you’re on your way. If it doesn’t, we can tow your vehicle to your mechanic or home, with the price in writing before we hook up.

Questions people ask

Why does my car just click when I try to start it?

A rapid click often means there isn't enough power to turn the starter. That usually points to a weak or dead battery, and a boost has a good chance of getting you going.

The battery seems fine but the car still won't start. What now?

If the engine cranks at normal speed but never fires, the problem may be fuel, ignition or something else. You'll probably need a tow to a mechanic who can find the real cause.

When do I need a tow instead of a boost?

When the vehicle won't start even with a boost, starts but dies again soon after, shows smoke, smells, grinding or warning lights, or the battery is visibly damaged.