Winter Car Care Tips
Winter is the hardest season for your car. Cold thickens the oil, saps the battery, drops tyre pressures, and road salt eats at the bodywork. A few hours of preparation in late autumn can be the difference between a car that starts first time on the coldest morning of the year and one that leaves you stranded. These winter car care tips cover everything worth checking before the first frost.
⚡ Quick Answer: Winter Car Care Tips
The most important winter car care tips are: get the battery load-tested before the first freeze, because a battery loses about 35 percent of its strength at freezing point and around 60 percent at 0 degrees Fahrenheit, while a cold engine can need up to twice the normal current to start. Check tyre tread, aim for 3 mm or more, and check pressures weekly since cold air lowers them. Test your antifreeze so it protects to at least minus 20 degrees, fill the washer bottle with proper winter screenwash, check every light, and keep an ice scraper, de-icer, torch, blanket and jump leads in the boot.
Battery: The Number One Winter Failure
A flat battery is the most common winter breakdown, and the reason is simple chemistry. Cold slows the chemical reaction inside the battery, so it produces less power, while at the same time a cold engine needs more power to turn over because the oil is thicker and everything is stiffer. The AAA Automotive Research Center reports that a battery loses about 35 percent of its strength at 32 degrees Fahrenheit (0 degrees Celsius) and about 60 percent at 0 degrees Fahrenheit, and a cold engine can need up to twice the normal current to start. A battery that just about copes in October can leave you stranded in December.
Most car batteries last three to five years. If yours is in that age range, or the engine cranks slowly on cold mornings, have it load-tested before winter. A proper load test measures the battery’s condition under load, which is different from simply checking its voltage, and most garages will do it free. Clean any corrosion from the terminals, make sure the connections are tight, and check the battery is held firmly in its tray, because vibration shortens its life. If your car has stop-start and heated screens and seats, the battery works harder still on every journey. You can read how a vehicle battery works on Wikipedia’s car battery page.
Tyres: Grip and Pressure in the Cold
Your tyres are the only part of the car touching the road, and in winter that contact matters more than at any other time of year. The legal minimum tread depth in the UK is 1.6 mm across the central three-quarters of the tread, but that is the legal limit, not a safe one. For winter, aim for 3 mm or more, because below 3 mm a tyre’s grip in the wet drops sharply and stopping distances grow longer. The quick check is a 20p coin: push it into the main tread grooves, and if you can see the outer band of the coin, the tread is close to the legal limit and the tyre should be looked at now.
Cold air contracts, so tyre pressures fall as the temperature drops, roughly 1 to 2 PSI for every 10 degrees Fahrenheit. A tyre that was correct in September can be soft by November. Underinflated tyres reduce traction, hurt fuel economy, wear unevenly and increase the risk of tyre failure. Check pressures weekly through winter, and check them when the tyres are cold, before you have driven anywhere. The correct pressures are in your handbook or on the sticker inside the driver’s door or fuel flap.
Winter tyres are worth considering if you live somewhere rural, hilly, or with regular snow. Their rubber compound stays soft below about 7 degrees Celsius, where ordinary tyres go hard and lose grip, and the difference on ice is significant. Many drivers follow the 7-for-7 rule: fit winter tyres once the temperature has stayed at or below 7 degrees for seven days in a row, and remove them when it stays at or above 7 degrees for seven days. For most town driving, decent all-season tyres with plenty of tread are fine. There is more detail on their design at Wikipedia’s winter tyre page.
Antifreeze and Coolant
Antifreeze does three jobs, and only one of them is in the name. It stops the coolant freezing, it stops the cooling system corroding from the inside, and it lubricates the water pump. Weak or old coolant fails at all three. Most cars use a 50/50 mix of antifreeze and water, and very cold climates can call for 60 or even 70 percent antifreeze, but never a richer mix than that, as Consumer Reports advises.
An antifreeze tester costs about £5 from any motor factor and tells you the temperature your coolant protects down to. For a UK winter, it should protect to at least minus 20 degrees. With the engine cold, check the level in the expansion tank is between the minimum and maximum marks, and never open the cap when the engine is hot. If the level keeps dropping, there is a leak that needs looking at. Do not mix different coolant types, because they can react with each other and block the system. For more on the chemistry, see Wikipedia’s antifreeze page.
Visibility: Wipers, Screenwash and Lights
On a frosty morning, clear the whole windscreen and every window, not just a small patch in the middle. That means a proper ice scraper and de-icer, never hot water, which can crack glass, and never a credit card or metal scraper that can scratch it. If your car has a heated windscreen or heated mirrors, use them, and clear snow from the roof as well, because it can slide onto the windscreen when you brake.
Fill the washer bottle with proper winter screenwash rated to at least minus 15 degrees, and do not over-dilute it just to make it last longer. Plain water can freeze in the pipes and crack them. Check the wiper blades too: they stiffen in the cold and can smear or tear. Replace them if they leave streaks, and lift them off the screen in freezing conditions if you park outside, so they do not freeze to the glass. Finally, walk around every light and check each one works, then clean them, because road salt and spray cut light output dramatically just when the days are shortest.
Oil and Other Fluids
Cold thickens engine oil, which makes cold starts harder and increases wear in the first minutes after starting. Check your handbook for the permitted grades: if a thinner winter grade such as 5W-30 is allowed instead of 10W-40, it can improve cold starting. Check the oil level before winter and top up if needed, but never overfill. Brake fluid, transmission fluid and power steering fluid should also be checked, because cold affects them too, and a low level can mean a leak. Windscreen washer fluid has already been covered, but it is worth repeating: it is the fluid drivers most often get wrong in winter, and it is also the easiest to fix.
If the weather is extremely cold, consider a block heater or a garage. An engine that starts warm uses less fuel, wears less and warms the cabin sooner. And if your car will be parked for a long time over winter, keep the fuel tank at least half full to reduce condensation inside the tank, and consider a trickle charger for the battery.
Protecting the Bodywork from Salt
Road salt is the slow enemy of winter. It does its job on the road and then eats away at your car’s underbody, wheel arches, brake lines and bodywork. The best defence is washing the car more often in winter, including the underside, and paying attention to the wheel arches where salt and mud collect. A coat of wax or sealant before winter helps, and it is worth fixing any stone chips or scratches before the cold arrives, because bare metal rusts fastest when it is wet and salty.
Do not forget the door and boot seals. A thin smear of silicone spray or petroleum jelly stops them freezing shut, which saves a torn seal and a morning of frustration. The same goes for the locks: a little de-icer in the keyhole, or better, keeping the car locked by remote so you never need the keyhole in the first place.
Winter Driving Habits
Good winter driving is smooth driving. Brake gently and early, steer smoothly, and leave much larger gaps than usual, because stopping distances on ice and snow can be many times longer than on a dry road. If the car has a winter driving mode, use it, and if it has traction control, leave it switched on. Avoid sudden acceleration, especially in a powerful car, and take corners at a speed that feels almost too slow.
Plan ahead: check the weather and road conditions before you set off, and delay the journey if the conditions are severe. Keep the fuel tank topped up, and charge your phone before you travel. If you get stuck, do not spin the wheels, which only polishes the ice underneath. Clear the snow from around the tyres, use a floor mat or grit for grip under the driven wheels, and rock the car gently between first gear and reverse if you have to.
What to Keep in the Boot
A simple emergency kit costs little and can save a very bad day. Keep an ice scraper and de-icer, a torch with fresh batteries, a warm blanket, a high-visibility vest, jump leads, a small shovel, a bag of grit or cat litter for traction, a bottle of water, and some snacks. Add a fully charged phone and, if you travel in rural areas, a portable phone charger. For more advice on keeping the car in shape year-round, see our Automotive guides, and our Travel section has tips for winter journeys.
Frequently Asked Questions
Should I warm up my car by idling it in winter?
Modern cars do not need long idling. Start the engine, wait about 30 seconds, then drive gently until it warms up. Driving warms the engine faster than idling, uses less fuel, and is better for the engine.
Can I use hot water to clear ice from my windscreen?
No. Pouring hot or boiling water onto a frozen windscreen can crack the glass because of the sudden temperature change. Use a scraper, de-icer spray, or the car’s heated windscreen.
How often should I check tyre pressure in winter?
Weekly, and always when the tyres are cold. Cold air lowers pressure by roughly 1 to 2 PSI for every 10 degrees Fahrenheit drop, so a tyre that was correct in autumn can be underinflated by midwinter.
Do I need winter tyres?
It depends on where you live and drive. Winter tyres make a real difference on snow and ice and in temperatures below about 7 degrees Celsius, so they are worth it in rural or hilly areas. For most town driving, good all-season tyres with at least 3 mm of tread are enough.
Why does my car battery die in winter?
Cold slows the chemical reaction in the battery, cutting its power by about 35 percent at freezing and around 60 percent at 0 degrees Fahrenheit, while the cold engine needs more power to start. If the battery is already three to five years old, a cold snap is often what finishes it.
