Winter Driving: Why Won't My Car Start?

By: Motor Easy
Why won't my Car Start in winter

As temperatures drop you're more likely to find your car won't start. Cold, damp weather increases the strain on vehicles, with adverse affects on your car's health; batteries, fuel systems, starter motors, alternators, oil and carburetors are most likely to see problems. 

If you're unsure about the health of your car book a free MotorEasy health check

We've listed potential causes for your problems and what can be done to prevent each.

(It's also a good time of year to ensure you've got breakdown cover to get you on your way if your car won't start!)


Car Won't Start: It Could Be Your Battery

Batteries are put under a lot of strain in cold weather - and are one of the most common causes of cars not starting. 


If you hear a faint whining noise when you turn the key, but if your starter motor doesn't turn over (the car 'coming to life'), it's probably a flat battery.

You might not hear anything if the battery is totally flat, or the cables have come loose.

Two other signs include the ignition lights on the dashboard failing to illuminate, and the car refusing to unlock with the central locking. 


If you desperately need to get moving, you can attempt to jump start your car. This does however mean you'll need jump cables and another vehicle.

If you think your battery needs replacing MotorEasy breakdown cover can get you to your local garage who will be able to help. If you've got a fitC device installed it will send a car battery alert to your phone.

Read our guide to checking your battery

Get MotorEasy Starter Battery Protection  


Car Won't Start: It Could Be Your Alternator

The alternator charges your car battery and works as an electrical generator when the engine is running. If you've changed your battery recently and it keeps going flat this could be the problem.


If your battery has died and you manage to jump start your car, but the battery dies again the alternator is probably where the problem lies.

Your headlights and dashboard lights might flicker, or your gauges move in a jerky way. You might even be able to smell burning, which could mean your alternator has recently overheated.


This one is best left to a mechanic, it should be easy to source a new part or MotorEasy can arrange a repair, making sure you get the best price for both parts and labour


Car Won't Start: It Could Be Your Starter Motor

This part does exactly what you think it does, it uses electricity to jolt your car's engine to life. 

Many modern cars have strong starter motors to cope with the demands of engines frequently turning on and off whilst in traffic.


A clicking sound when you turn the key is the most obvious sign of a broken starter motor along with the engine refusing to turn over.

All the lights on your dashboard will also illuminate, pointing to an issue with your starter motor rather than your battery.


You won't be able to jump start your car if the starter motor has failed so again this is one for a mechanic. They aren't expensive but the work can take up to half a day in labour which adds up. MotorEasy can arrange these repairs done locally at the best price. 


Car Won't Start: It Could Be The Fuel System

There's a chance, over time, that fuel systems can become contaminated with water. As we reach freezing conditions this water can freeze, preventing the engine from running altogether.

The issue tends to be the most problematic in fuel lines, which feed fuel injectors and can get blocked by tiny ice particles, starving the engine of fuel.


Your engine won't start, and if it does it may feel stuttery when accelerating with a general jerky feel to the car.

You could also find that your car engine completely cuts out whilst you're driving.


If it turns out your car does have water in the fuel lines it may need to be professionally flushed. 

You can however use certain additives to reduce the chances of water entering the system, such as alcohol, which holds the water in suspension before passing it through the exhaust system.

If you keep your car's fuel tank as close to full as possible it reduces this likelihood. You should also remember that diesel can become 'thicker' in cold conditions - another obstacle for your car in chilly conditions. 

Read our winter breakdown checklist


Car Won't Start: Are You Using The Right Oil?

Another thing that can become less free flowing in winter is the oil in your car. This, in turn, puts more strain on your battery making it harder for the engine to turn over.


The cold viscosity (or thickness) of your oil could be too much for your car to start in cooler temperatures. On the other hand too much hot viscosity will mean your engine components aren't protected properly and could be subjected to premature wear. 


Your car's handbook will be able to tell you what oil your manufacturer recommends, and you could try switching to a thinner oil in winter. 

Typically it will be grades 10W-30 and 5W-20 with the first number letting you know how thick the oil is, and the W standing for winter. The lower the number, the thinner the oil.

Read our car oil guide


Car Won't Start: It Could Be Your Carburetor

This problem will only affect those of you that have cars older than 30 years (newer cars don't have carburetors). Carburetors regulate the mixing of fuel and air and are vulnerable to icing up in cold conditions. 


If your carburetor nozzles become clogged with ice the engine probably won't start and if it does it won't run properly.


When starting your car it's recommeded you put your left foot on the clutch and gently push the accelerator pedal when you start the engine in cold weather.

This will give your engine a little helping hand by pre-injecting a small quantity of fuel.

5 benefits of regularly servicing older or classic cars


Can't Get In Your Car?

If you're having trouble getting in your car, try using some silicone-based furniture polish around the rubber door seals to prevent them getting stuck when it freezes. We recommend applying it with a cloth so you don't get it on the paintwork.

If your locks are frozen, try warming up your key or spraying some anti-freeze into the lock, WD40 also does the trick. 


Check Your Cars Health

If you've done all the above and there's still something wrong with your car MotorEasy can help. We can diagnose your car and save you money on the repairs all with your own engineer to monitor the booking from start to finish. 

Book A Diagnosis


Further Winter Driving Reading

Winter Driving- Don't Get Fined On Cold Mornings

Winter Driving - Do You Really Need Winter Tyres?

Winter Driving - How To Prepare Your Car For Winter

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