Car won't start? Work out which problem you have before you call

"It won't start" covers about six different faults. Before you call anyone, work out which one you've got — it changes what happens next, and sometimes it means you don't need a tow at all.

Nothing at all. No lights, no click.

Dead battery, or a connection problem. Check the terminals. Corrosion looks like blue-green crust, and a loose clamp you can twist by hand is enough to cause this.

If a jump start brings it back, the question becomes why it went flat. Which we'll come back to.

One loud click, then silence

Usually the starter solenoid engaging but the motor not turning. Sometimes it's a badly discharged battery, sometimes it's the starter itself.

Old trick that still works often enough to mention: a firm tap on the starter body with a hammer while someone turns the key. If it fires, your starter is on its way out and you've bought yourself a drive to the shop rather than a tow.

Rapid clicking

Not enough current to hold the solenoid in. Almost always the battery, or a connection so poor it may as well be.

Cranks normally but won't fire

The battery and starter are fine — you have a fuel, spark or timing problem. This is the one that needs diagnosis, and there's not much you can check in a driveway.

One thing worth knowing: if the engine cranks noticeably faster and more freely than usual, and it's a car with a timing belt, stop cranking it. That can be a snapped belt, and on an interference engine, continued cranking is what turns a belt job into an engine.

Starts, then dies immediately

Often an immobiliser or security fault, sometimes fuel delivery. If your dash shows a key or padlock symbol, it's the immobiliser and a second key is worth trying.

Fine yesterday, dead today, over and over

This is a parasitic drain — something staying awake after you lock the car and pulling current all night. Aftermarket stereos, alarms, a glovebox light that never goes off, a failing module.

People replace two or three batteries chasing this before someone actually measures it. Measuring takes an hour and finds it. That's the sort of thing we test rather than guess at.

Why this all happens in October

Cold weather doesn't create battery faults, it exposes them. A battery loses a chunk of its cranking power near freezing, at the same moment thickened oil makes the engine harder to turn. A battery that's been quietly marginal since June fails on the first cold morning in Graham.

Which is why every autumn we see a wave of no-starts in the same week. If yours has been cranking slowly, get it load-tested before the weather turns. It's a ten-minute test.